diff --git a/apps/meteor/app/autotranslate/client/lib/actionButton.ts b/apps/meteor/app/autotranslate/client/lib/actionButton.ts
index 742ea4c9a5b79..4b12d7ec0017e 100644
--- a/apps/meteor/app/autotranslate/client/lib/actionButton.ts
+++ b/apps/meteor/app/autotranslate/client/lib/actionButton.ts
@@ -1,7 +1,3 @@
-import { Meteor } from 'meteor/meteor';
-
 import { AutoTranslate } from './autotranslate';
 
-Meteor.startup(() => {
-	AutoTranslate.init();
-});
+AutoTranslate.init();
diff --git a/apps/meteor/app/autotranslate/client/lib/autotranslate.ts b/apps/meteor/app/autotranslate/client/lib/autotranslate.ts
index 1c294c2023137..9ab66e6086efc 100644
--- a/apps/meteor/app/autotranslate/client/lib/autotranslate.ts
+++ b/apps/meteor/app/autotranslate/client/lib/autotranslate.ts
@@ -1,13 +1,11 @@
 import type { IRoom, ISubscription, ISupportedLanguage, ITranslatedMessage, MessageAttachmentDefault } from '@rocket.chat/core-typings';
 import { isTranslatedMessageAttachment } from '@rocket.chat/core-typings';
 import mem from 'mem';
-import { Meteor } from 'meteor/meteor';
-import { Tracker } from 'meteor/tracker';
 
+import { PermissionsCachedStore } from '../../../../client/cachedStores';
 import { settings } from '../../../../client/lib/settings';
-import { getUserId } from '../../../../client/lib/user';
-import { watchUser, watchUserId } from '../../../../client/meteor/user';
-import { Messages, Subscriptions } from '../../../../client/stores';
+import { getUserId, userIdStore } from '../../../../client/lib/user';
+import { Messages, Subscriptions, Users } from '../../../../client/stores';
 import {
 	hasTranslationLanguageInAttachments,
 	hasTranslationLanguageInMessage,
@@ -18,15 +16,16 @@ import { sdk } from '../../../utils/client/lib/SDKClient';
 let userLanguage = 'en';
 let username = '';
 
-Meteor.startup(() => {
-	Tracker.autorun(() => {
-		const user = watchUser();
-		if (!user) return;
-
-		userLanguage = user.language || 'en';
-		username = user.username || '';
-	});
-});
+const refreshUserCache = () => {
+	const uid = userIdStore.getState();
+	const user = uid ? Users.use.getState().get(uid) : undefined;
+	if (!user) return;
+	userLanguage = user.language || 'en';
+	username = user.username || '';
+};
+refreshUserCache();
+userIdStore.subscribe(refreshUserCache);
+Users.use.subscribe(refreshUserCache);
 
 export const AutoTranslate = {
 	initialized: false,
@@ -84,14 +83,7 @@ export const AutoTranslate = {
 			return;
 		}
 
-		Tracker.autorun(async (c) => {
-			const uid = watchUserId();
-			if (!settings.watch('AutoTranslate_Enabled') || !uid || !hasPermission('auto-translate')) {
-				return;
-			}
-
-			c.stop();
-
+		const loadProviders = async () => {
 			try {
 				[this.providersMetadata, this.supportedLanguages] = await Promise.all([
 					sdk.call('autoTranslate.getProviderUiMetadata'),
@@ -101,7 +93,25 @@ export const AutoTranslate = {
 				// Avoid unwanted error message on UI when autotranslate is disabled while fetching data
 				console.error((e as Error).message);
 			}
-		});
+		};
+
+		let loaded = false;
+		const unsubs: Array<() => void> = [];
+		const tryLoad = async () => {
+			if (loaded) return;
+			if (!settings.peek('AutoTranslate_Enabled') || !userIdStore.getState() || !hasPermission('auto-translate')) {
+				return;
+			}
+			loaded = true;
+			unsubs.splice(0).forEach((unsubscribe) => unsubscribe());
+			await loadProviders();
+		};
+
+		unsubs.push(userIdStore.subscribe(() => void tryLoad()));
+		unsubs.push(settings.observe('AutoTranslate_Enabled', () => void tryLoad()));
+		unsubs.push(PermissionsCachedStore.useReady.subscribe(() => void tryLoad()));
+
+		void tryLoad();
 
 		Subscriptions.use.subscribe(() => {
 			mem.clear(this.findSubscriptionByRid);
diff --git a/apps/meteor/app/lib/client/index.ts b/apps/meteor/app/lib/client/index.ts
index 2769be7fe5764..2d07fbe1ac5b4 100644
--- a/apps/meteor/app/lib/client/index.ts
+++ b/apps/meteor/app/lib/client/index.ts
@@ -1,3 +1,2 @@
 import '../lib/MessageTypes';
 import './OAuthProxy';
-import './methods/sendMessage';
diff --git a/apps/meteor/app/lib/client/methods/sendMessage.ts b/apps/meteor/app/lib/client/methods/sendMessage.ts
index 0969ea8d9cf36..8644191c21542 100644
--- a/apps/meteor/app/lib/client/methods/sendMessage.ts
+++ b/apps/meteor/app/lib/client/methods/sendMessage.ts
@@ -1,7 +1,5 @@
 import type { IMessage } from '@rocket.chat/core-typings';
-import type { ServerMethods } from '@rocket.chat/ddp-client';
 import { clientCallbacks } from '@rocket.chat/ui-client';
-import { Meteor } from 'meteor/meteor';
 
 import { onClientMessageReceived } from '../../../../client/lib/onClientMessageReceived';
 import { settings } from '../../../../client/lib/settings';
@@ -11,40 +9,41 @@ import { Messages, Rooms } from '../../../../client/stores';
 import { trim } from '../../../../lib/utils/stringUtils';
 import { t } from '../../../utils/lib/i18n';
 
-Meteor.methods<ServerMethods>({
-	async sendMessage(message) {
-		const uid = getUserId();
-		if (!uid || trim(message.msg) === '') {
-			return false;
-		}
-		const messageAlreadyExists = message._id && Messages.state.get(message._id);
-		if (messageAlreadyExists) {
-			return dispatchToastMessage({ type: 'error', message: t('Message_Already_Sent') });
-		}
-		const user = getUser();
-		if (!user?.username) {
-			throw new Meteor.Error('error-invalid-user', 'Invalid user', { method: 'sendMessage' });
-		}
-		message.ts = new Date();
-		message.u = {
+export const runOptimisticSendMessage = async (
+	message: Partial<IMessage> & { rid: IMessage['rid']; msg: IMessage['msg'] },
+): Promise<void> => {
+	const uid = getUserId();
+	if (!uid || trim(message.msg) === '') {
+		return;
+	}
+	const messageAlreadyExists = message._id && Messages.state.get(message._id);
+	if (messageAlreadyExists) {
+		dispatchToastMessage({ type: 'error', message: t('Message_Already_Sent') });
+		return;
+	}
+	const user = getUser();
+	if (!user?.username) {
+		return;
+	}
+
+	const room = Rooms.state.get(message.rid);
+	if (room?.federated) {
+		return;
+	}
+
+	const optimistic: IMessage = {
+		...(message as IMessage),
+		ts: new Date(),
+		u: {
 			_id: uid,
 			username: user.username,
 			name: user.name || '',
-		};
-		message.temp = true;
-		if (settings.peek('Message_Read_Receipt_Enabled')) {
-			message.unread = true;
-		}
-
-		// If the room is federated, send the message to matrix only
-		const room = Rooms.state.get(message.rid);
-		if (room?.federated) {
-			return;
-		}
+		},
+		temp: true,
+		...(settings.peek('Message_Read_Receipt_Enabled') ? { unread: true } : {}),
+	};
 
-		await onClientMessageReceived(message as IMessage).then((message) => {
-			Messages.state.store(message);
-			return clientCallbacks.run('afterSaveMessage', message, { room, user });
-		});
-	},
-});
+	const processed = await onClientMessageReceived(optimistic);
+	Messages.state.store(processed);
+	await clientCallbacks.run('afterSaveMessage', processed, { room, user });
+};
diff --git a/apps/meteor/app/livechat/client/lib/stream/queueManager.ts b/apps/meteor/app/livechat/client/lib/stream/queueManager.ts
index 5fc9be444ec98..ed48999575202 100644
--- a/apps/meteor/app/livechat/client/lib/stream/queueManager.ts
+++ b/apps/meteor/app/livechat/client/lib/stream/queueManager.ts
@@ -5,7 +5,6 @@ import {
 	type IOmnichannelAgent,
 	type Serialized,
 } from '@rocket.chat/core-typings';
-import { Tracker } from 'meteor/tracker';
 
 import { useLivechatInquiryStore } from '../../../../../client/hooks/useLivechatInquiryStore';
 import { queryClient } from '../../../../../client/lib/queryClient';
@@ -64,8 +63,10 @@ const removeInquiry = async (inquiry: ILivechatInquiryRecord) => {
 	return queryClient.invalidateQueries({ queryKey: ['rooms', { reference: inquiry.rid, type: 'l' }] });
 };
 
+const INQUIRY_COUNT_SETTING = 'Livechat_guest_pool_max_number_incoming_livechats_displayed';
+
 const getInquiriesFromAPI = async () => {
-	const count = settings.peek('Livechat_guest_pool_max_number_incoming_livechats_displayed') ?? 0;
+	const count = settings.peek<number>(INQUIRY_COUNT_SETTING) ?? 0;
 	const { inquiries } = await sdk.rest.get('/v1/livechat/inquiries.queuedForUser', { count });
 	return inquiries;
 };
@@ -140,10 +141,12 @@ const subscribe = async (userId: IOmnichannelAgent['_id']) => {
 		const cleanDepartmentListeners = addListenerForeachDepartment(agentDepartments);
 		const globalCleanup = addGlobalListener();
 
-		const computation = Tracker.autorun(async () => {
-			const inquiriesFromAPI = await getInquiriesFromAPI();
+		const refetchInquiries = async () => updateInquiries(await getInquiriesFromAPI());
+
+		await refetchInquiries();
 
-			await updateInquiries(inquiriesFromAPI);
+		const unobserveInquiryCount = settings.observe(INQUIRY_COUNT_SETTING, () => {
+			void refetchInquiries();
 		});
 
 		return () => {
@@ -152,8 +155,8 @@ const subscribe = async (userId: IOmnichannelAgent['_id']) => {
 			cleanAgentListener?.();
 			cleanDepartmentListeners?.();
 			globalCleanup?.();
+			unobserveInquiryCount();
 			departments.clear();
-			computation.stop();
 		};
 	} catch (error) {
 		dispatchToastMessage({ type: 'error', message: error });
diff --git a/apps/meteor/app/reactions/client/index.ts b/apps/meteor/app/reactions/client/index.ts
deleted file mode 100644
index 935ab48e93ad6..0000000000000
--- a/apps/meteor/app/reactions/client/index.ts
+++ /dev/null
@@ -1 +0,0 @@
-import './methods/setReaction';
diff --git a/apps/meteor/app/reactions/client/methods/setReaction.ts b/apps/meteor/app/reactions/client/methods/setReaction.ts
index 96cd4bcb95910..093fdd9ea2b0c 100644
--- a/apps/meteor/app/reactions/client/methods/setReaction.ts
+++ b/apps/meteor/app/reactions/client/methods/setReaction.ts
@@ -1,84 +1,81 @@
 import type { IMessage } from '@rocket.chat/core-typings';
-import type { ServerMethods } from '@rocket.chat/ddp-client';
-import { Meteor } from 'meteor/meteor';
 
 import { roomCoordinator } from '../../../../client/lib/rooms/roomCoordinator';
 import { getUser, getUserId } from '../../../../client/lib/user';
 import { Rooms, Subscriptions, Messages } from '../../../../client/stores';
 import { emoji } from '../../../emoji/client';
 
-Meteor.methods<ServerMethods>({
-	async setReaction(reaction, messageId) {
-		if (!getUserId()) {
-			throw new Meteor.Error(203, 'User_logged_out');
-		}
-
-		const user = getUser();
+export const runOptimisticSetReaction = (reaction: string, messageId: IMessage['_id']): void => {
+	if (!getUserId()) {
+		return;
+	}
 
-		if (!user?.username) {
-			return false;
-		}
+	const user = getUser();
+	if (!user?.username) {
+		return;
+	}
 
-		const message: IMessage | undefined = Messages.state.get(messageId);
-		if (!message) {
-			return false;
-		}
+	const message: IMessage | undefined = Messages.state.get(messageId);
+	if (!message) {
+		return;
+	}
 
-		const room = Rooms.state.get(message.rid);
-		if (!room) {
-			return false;
-		}
-
-		if (message.private) {
-			return false;
-		}
+	const room = Rooms.state.get(message.rid);
+	if (!room) {
+		return;
+	}
 
-		if (!emoji.list[reaction]) {
-			return false;
-		}
+	if (message.private) {
+		return;
+	}
 
-		if (roomCoordinator.readOnly(room, user)) {
-			return false;
-		}
+	if (!emoji.list[reaction]) {
+		return;
+	}
 
-		if (!Subscriptions.state.find(({ rid }) => rid === message.rid)) {
-			return false;
-		}
+	if (roomCoordinator.readOnly(room, user)) {
+		return;
+	}
 
-		if (message.reactions?.[reaction] && message.reactions[reaction].usernames.indexOf(user.username) !== -1) {
-			message.reactions[reaction].usernames.splice(message.reactions[reaction].usernames.indexOf(user.username), 1);
+	if (!Subscriptions.state.find(({ rid }) => rid === message.rid)) {
+		return;
+	}
 
-			if (message.reactions[reaction].usernames.length === 0) {
-				delete message.reactions[reaction];
-			}
+	if (message.reactions?.[reaction] && message.reactions[reaction].usernames.indexOf(user.username) !== -1) {
+		message.reactions[reaction].usernames.splice(message.reactions[reaction].usernames.indexOf(user.username), 1);
 
-			if (!message.reactions || typeof message.reactions !== 'object' || Object.keys(message.reactions).length === 0) {
-				delete message.reactions;
-				Messages.state.update(
-					(record) => record._id === messageId,
-					({ reactions: _, ...record }) => record,
-				);
-			} else {
-				Messages.state.update(
-					(record) => record._id === messageId,
-					(record) => ({ ...record, reactions: message.reactions }),
-				);
-			}
-		} else {
-			if (!message.reactions) {
-				message.reactions = {};
-			}
-			if (!message.reactions[reaction]) {
-				message.reactions[reaction] = {
-					usernames: [],
-				};
-			}
-			message.reactions[reaction].usernames.push(user.username);
+		if (message.reactions[reaction].usernames.length === 0) {
+			delete message.reactions[reaction];
+		}
 
+		if (!message.reactions || typeof message.reactions !== 'object' || Object.keys(message.reactions).length === 0) {
+			delete message.reactions;
 			Messages.state.update(
 				(record) => record._id === messageId,
-				(record) => ({ ...record, reactions: message.reactions }),
+				({ reactions: _, ...record }) => record,
 			);
+			return;
 		}
-	},
-});
+
+		Messages.state.update(
+			(record) => record._id === messageId,
+			(record) => ({ ...record, reactions: message.reactions }),
+		);
+		return;
+	}
+
+	if (!message.reactions) {
+		message.reactions = {};
+	}
+	if (!message.reactions[reaction]) {
+		message.reactions[reaction] = {
+			usernames: [],
+		};
+	}
+	message.reactions[reaction].usernames.push(user.username);
+
+	Messages.state.update(
+		(record) => record._id === messageId,
+		(record) => ({ ...record, reactions: message.reactions }),
+	);
+};
diff --git a/apps/meteor/app/slashcommands-join/client/client.ts b/apps/meteor/app/slashcommands-join/client/client.ts
index bc8d589f51ac4..878981a11951c 100644
--- a/apps/meteor/app/slashcommands-join/client/client.ts
+++ b/apps/meteor/app/slashcommands-join/client/client.ts
@@ -1,5 +1,3 @@
-import type { Meteor } from 'meteor/meteor';
-
 import { slashCommands } from '../../utils/client/slashCommand';
 
 slashCommands.add({
@@ -10,7 +8,7 @@ slashCommands.add({
 		permission: 'view-c-room',
 	},
 	result(err, _result: unknown, params: Record<string, any>) {
-		if ((err as Meteor.Error).error === 'error-user-already-in-room') {
+		if ((err as { error?: string } | undefined)?.error === 'error-user-already-in-room') {
 			params.cmd = 'open';
 			params.msg.msg = params.msg.msg.replace('join', 'open');
 			return void slashCommands.run({ command: 'open', params: params.params, message: params.msg, triggerId: '', userId: params.userId });
diff --git a/apps/meteor/app/ui-utils/client/lib/RoomHistoryManager.ts b/apps/meteor/app/ui-utils/client/lib/RoomHistoryManager.ts
index 14b1d291ef016..c6ce002b70c12 100644
--- a/apps/meteor/app/ui-utils/client/lib/RoomHistoryManager.ts
+++ b/apps/meteor/app/ui-utils/client/lib/RoomHistoryManager.ts
@@ -1,8 +1,7 @@
 import type { IMessage, IRoom, ISubscription } from '@rocket.chat/core-typings';
 import { Emitter } from '@rocket.chat/emitter';
 import { differenceInMilliseconds } from 'date-fns';
-import { ReactiveVar } from 'meteor/reactive-var';
-import { Tracker } from 'meteor/tracker';
+import { useCallback, useSyncExternalStore } from 'react';
 import type { MutableRefObject } from 'react';
 
 import { onClientMessageReceived } from '../../../../client/lib/onClientMessageReceived';
@@ -13,8 +12,6 @@ import { waitForElement } from '../../../../client/lib/utils/waitForElement';
 import { Messages, Subscriptions } from '../../../../client/stores';
 import { getUserPreference } from '../../../utils/client';
 
-const waitAfterFlush = () => new Promise((resolve) => Tracker.afterFlush(() => resolve(void 0)));
-
 const processMessage = async (msg: IMessage & { ignored?: boolean }, { subscription }: { subscription?: ISubscription }) => {
 	const userId = msg.u?._id;
 
@@ -46,36 +43,37 @@ export async function upsertMessageBulk({
 
 const defaultLimit = parseInt(getConfig('roomListLimit') ?? '50') || 50;
 
+export type RoomHistoryState = {
+	hasMore: boolean;
+	hasMoreNext: boolean;
+	isLoading: boolean;
+	unreadNotLoaded: number;
+	firstUnread: IMessage | undefined;
+	loaded: number | undefined;
+	oldestTs?: Date;
+	scroll?: {
+		scrollHeight: number;
+		scrollTop: number;
+	};
+};
+
+const roomStateEvent = (rid: IRoom['_id']) => `state:${rid}` as const;
+
 class RoomHistoryManagerClass extends Emitter {
 	private lastRequest?: Date;
 
-	private histories: Record<
-		IRoom['_id'],
-		{
-			hasMore: ReactiveVar<boolean>;
-			hasMoreNext: ReactiveVar<boolean>;
-			isLoading: ReactiveVar<boolean>;
-			unreadNotLoaded: ReactiveVar<number>;
-			firstUnread: ReactiveVar<IMessage | undefined>;
-			loaded: number | undefined;
-			oldestTs?: Date;
-			scroll?: {
-				scrollHeight: number;
-				scrollTop: number;
-			};
-		}
-	> = {};
+	private histories: Record<IRoom['_id'], RoomHistoryState> = {};
 
 	private requestsList: string[] = [];
 
-	public getRoom(rid: IRoom['_id']) {
+	public getRoom(rid: IRoom['_id']): RoomHistoryState {
 		if (!this.histories[rid]) {
 			this.histories[rid] = {
-				hasMore: new ReactiveVar(true),
-				hasMoreNext: new ReactiveVar(false),
-				isLoading: new ReactiveVar(false),
-				unreadNotLoaded: new ReactiveVar(0),
-				firstUnread: new ReactiveVar(undefined),
+				hasMore: true,
+				hasMoreNext: false,
+				isLoading: false,
+				unreadNotLoaded: 0,
+				firstUnread: undefined,
 				loaded: undefined,
 			};
 		}
@@ -83,6 +81,16 @@ class RoomHistoryManagerClass extends Emitter {
 		return this.histories[rid];
 	}
 
+	public updateRoom(rid: IRoom['_id'], patch: Partial<RoomHistoryState>): void {
+		const room = this.getRoom(rid);
+		Object.assign(room, patch);
+		this.emit(roomStateEvent(rid), room);
+	}
+
+	public subscribeToRoom(rid: IRoom['_id'], cb: (state: RoomHistoryState) => void): () => void {
+		return this.on(roomStateEvent(rid), cb);
+	}
+
 	private async queue(): Promise<void> {
 		return new Promise((resolve) => {
 			const requestId = crypto.randomUUID();
@@ -122,12 +130,12 @@ class RoomHistoryManagerClass extends Emitter {
 	public async getMore(rid: IRoom['_id'], { limit = defaultLimit }: { limit?: number } = {}): Promise<void> {
 		const room = this.getRoom(rid);
 
-		if (Tracker.nonreactive(() => room.hasMore.get()) !== true) {
+		if (room.hasMore !== true) {
 			return;
 		}
 
 		try {
-			room.isLoading.set(true);
+			this.updateRoom(rid, { isLoading: true });
 
 			await this.queue();
 
@@ -155,8 +163,10 @@ class RoomHistoryManagerClass extends Emitter {
 			this.unqueue();
 
 			const { messages = [] } = result;
-			room.unreadNotLoaded.set(result.unreadNotLoaded);
-			room.firstUnread.set(result.firstUnread);
+			this.updateRoom(rid, {
+				unreadNotLoaded: result.unreadNotLoaded,
+				firstUnread: result.firstUnread,
+			});
 
 			if (messages.length > 0) {
 				room.oldestTs = messages[messages.length - 1].ts;
@@ -185,17 +195,16 @@ class RoomHistoryManagerClass extends Emitter {
 			room.loaded += visibleMessages.length;
 
 			if (messages.length < limit) {
-				room.hasMore.set(false);
+				this.updateRoom(rid, { hasMore: false });
 			}
 
-			if (room.hasMore.get() && (visibleMessages.length === 0 || room.loaded < limit)) {
+			if (room.hasMore && (visibleMessages.length === 0 || room.loaded < limit)) {
 				return this.getMore(rid);
 			}
 
 			this.emit('loaded-messages');
 		} finally {
-			room.isLoading.set(false);
-			await waitAfterFlush();
+			this.updateRoom(rid, { isLoading: false });
 		}
 	}
 
@@ -218,14 +227,14 @@ class RoomHistoryManagerClass extends Emitter {
 
 	public async getMoreNext(rid: IRoom['_id'], atBottomRef: MutableRefObject<boolean>) {
 		const room = this.getRoom(rid);
-		if (Tracker.nonreactive(() => room.hasMoreNext.get()) !== true) {
+		if (room.hasMoreNext !== true) {
 			return;
 		}
 
 		await this.queue();
 		atBottomRef.current = false;
 
-		room.isLoading.set(true);
+		this.updateRoom(rid, { isLoading: true });
 
 		const lastMessage = Messages.state.findFirst(
 			(record) => record.rid === rid && record._hidden !== true,
@@ -244,27 +253,25 @@ class RoomHistoryManagerClass extends Emitter {
 
 			this.emit('loaded-messages');
 
-			room.isLoading.set(false);
+			this.updateRoom(rid, { isLoading: false });
 			if (!room.loaded) {
 				room.loaded = 0;
 			}
 
 			room.loaded += result.messages.length;
 			if (result.messages.length < defaultLimit) {
-				room.hasMoreNext.set(false);
+				this.updateRoom(rid, { hasMoreNext: false });
 			}
 		}
 		this.unqueue();
 	}
 
 	public hasMore(rid: IRoom['_id']) {
-		const room = this.getRoom(rid);
-		return room.hasMore.get();
+		return this.getRoom(rid).hasMore;
 	}
 
 	public hasMoreNext(rid: IRoom['_id']) {
-		const room = this.getRoom(rid);
-		return room.hasMoreNext.get();
+		return this.getRoom(rid).hasMoreNext;
 	}
 
 	public getMoreIfIsEmpty(rid: IRoom['_id']) {
@@ -276,8 +283,7 @@ class RoomHistoryManagerClass extends Emitter {
 	}
 
 	public isLoading(rid: IRoom['_id']) {
-		const room = this.getRoom(rid);
-		return room.isLoading.get();
+		return this.getRoom(rid).isLoading;
 	}
 
 	public close(rid: IRoom['_id']) {
@@ -288,11 +294,13 @@ class RoomHistoryManagerClass extends Emitter {
 	public clear(rid: IRoom['_id']) {
 		const room = this.getRoom(rid);
 		Messages.state.remove((record) => record.rid === rid);
-		room.isLoading.set(false);
-		room.hasMore.set(true);
-		room.hasMoreNext.set(false);
 		room.oldestTs = undefined;
 		room.loaded = undefined;
+		this.updateRoom(rid, {
+			isLoading: false,
+			hasMore: true,
+			hasMoreNext: false,
+		});
 	}
 
 	public async getSurroundingMessages(message?: Pick<IMessage, '_id' | 'rid'> & { ts?: Date }) {
@@ -332,18 +340,24 @@ class RoomHistoryManagerClass extends Emitter {
 
 		await upsertMessageBulk({ msgs: Array.from(result.messages).filter((msg) => msg.t !== 'command'), subscription });
 
-		Tracker.afterFlush(async () => {
-			this.emit('loaded-messages');
-			room.isLoading.set(false);
-		});
+		this.emit('loaded-messages');
+		this.updateRoom(message.rid, { isLoading: false });
 
 		if (!room.loaded) {
 			room.loaded = 0;
 		}
 		room.loaded += result.messages.length;
-		room.hasMore.set(result.moreBefore);
-		room.hasMoreNext.set(result.moreAfter);
+		this.updateRoom(message.rid, {
+			hasMore: result.moreBefore,
+			hasMoreNext: result.moreAfter,
+		});
 	}
 }
 
 export const RoomHistoryManager = new RoomHistoryManagerClass();
+
+export const useRoomHistoryState = <T>(rid: IRoom['_id'], selector: (state: RoomHistoryState) => T): T =>
+	useSyncExternalStore(
+		useCallback((onStoreChange) => RoomHistoryManager.subscribeToRoom(rid, onStoreChange), [rid]),
+		() => selector(RoomHistoryManager.getRoom(rid)),
+	);
diff --git a/apps/meteor/app/ui/client/lib/recorderjs/AudioEncoder.ts b/apps/meteor/app/ui/client/lib/recorderjs/AudioEncoder.ts
index 2360c69e354aa..68665ecede78a 100644
--- a/apps/meteor/app/ui/client/lib/recorderjs/AudioEncoder.ts
+++ b/apps/meteor/app/ui/client/lib/recorderjs/AudioEncoder.ts
@@ -1,5 +1,4 @@
 import { Emitter } from '@rocket.chat/emitter';
-import { Meteor } from 'meteor/meteor';
 
 export class AudioEncoder extends Emitter {
 	private worker: Worker;
@@ -9,7 +8,7 @@ export class AudioEncoder extends Emitter {
 	constructor(source: MediaStreamAudioSourceNode, { bufferLen = 4096, numChannels = 1, bitRate = 32 } = {}) {
 		super();
 
-		const workerPath = Meteor.absoluteUrl('workers/mp3-encoder/index.js');
+		const workerPath = new URL('workers/mp3-encoder/index.js', __meteor_runtime_config__.ROOT_URL).toString();
 
 		this.worker = new Worker(workerPath);
 		this.worker.onmessage = this.handleWorkerMessage;
diff --git a/apps/meteor/app/ui/client/lib/recorderjs/videoRecorder.spec.ts b/apps/meteor/app/ui/client/lib/recorderjs/videoRecorder.spec.ts
index f0a4e58f8a6f8..3ef71d274e547 100644
--- a/apps/meteor/app/ui/client/lib/recorderjs/videoRecorder.spec.ts
+++ b/apps/meteor/app/ui/client/lib/recorderjs/videoRecorder.spec.ts
@@ -1,18 +1,6 @@
 import { VideoRecorder } from './videoRecorder';
 import { createDeferredPromise } from '../../../../../tests/mocks/utils/createDeferredMockFn';
 
-jest.mock('meteor/reactive-var', () => ({
-	ReactiveVar: jest.fn().mockImplementation((initialValue) => {
-		let value = initialValue;
-		return {
-			get: jest.fn(() => value),
-			set: jest.fn((newValue) => {
-				value = newValue;
-			}),
-		};
-	}),
-}));
-
 describe('VideoRecorder', () => {
 	let mockStream: MediaStream;
 	let mockVideoTrack: MediaStreamTrack;
@@ -93,7 +81,7 @@ describe('VideoRecorder', () => {
 			streamDeferred.resolve(mockStream);
 			await jest.runAllTimersAsync();
 
-			expect(VideoRecorder.cameraStarted.get()).toBe(false);
+			expect(VideoRecorder.cameraStarted).toBe(false);
 		});
 
 		it('should handle multiple start/stop cycles', async () => {
@@ -115,7 +103,7 @@ describe('VideoRecorder', () => {
 			await jest.runAllTimersAsync();
 
 			expect(cb).toHaveBeenCalledWith(true);
-			expect(VideoRecorder.cameraStarted.get()).toBe(true);
+			expect(VideoRecorder.cameraStarted).toBe(true);
 		});
 
 		it('should invalidate pending callbacks from previous start when new start is called', async () => {
@@ -155,19 +143,19 @@ describe('VideoRecorder', () => {
 			await jest.runAllTimersAsync();
 
 			expect(cb).toHaveBeenCalledWith(true);
-			expect(VideoRecorder.cameraStarted.get()).toBe(true);
+			expect(VideoRecorder.cameraStarted).toBe(true);
 		});
 
 		it('should stop camera tracks', () => {
 			(VideoRecorder as any).stream = mockStream;
 			(VideoRecorder as any).started = true;
-			VideoRecorder.cameraStarted.set(true);
+			(VideoRecorder as any)._cameraStarted = true;
 
 			VideoRecorder.stop();
 
 			expect(mockVideoTrack.stop).toHaveBeenCalled();
 			expect(mockAudioTrack.stop).toHaveBeenCalled();
-			expect(VideoRecorder.cameraStarted.get()).toBe(false);
+			expect(VideoRecorder.cameraStarted).toBe(false);
 		});
 
 		it('should return supported mime types', () => {
diff --git a/apps/meteor/app/ui/client/lib/recorderjs/videoRecorder.ts b/apps/meteor/app/ui/client/lib/recorderjs/videoRecorder.ts
index 0557f4706cd8b..53cd04eaa5be6 100644
--- a/apps/meteor/app/ui/client/lib/recorderjs/videoRecorder.ts
+++ b/apps/meteor/app/ui/client/lib/recorderjs/videoRecorder.ts
@@ -1,13 +1,16 @@
-import { ReactiveVar } from 'meteor/reactive-var';
+import { Emitter } from '@rocket.chat/emitter';
+import { useCallback, useSyncExternalStore } from 'react';
 
-class VideoRecorder {
-	public cameraStarted = new ReactiveVar(false);
+type VideoRecorderEvents = {
+	cameraStartedChange: boolean;
+};
 
-	private started = false;
+class VideoRecorder extends Emitter<VideoRecorderEvents> {
+	private _cameraStarted = false;
 
-	private recording = new ReactiveVar(false);
+	private started = false;
 
-	private recordingAvailable = new ReactiveVar(false);
+	private recordingAvailable = false;
 
 	private videoel: HTMLVideoElement | undefined;
 
@@ -19,6 +22,18 @@ class VideoRecorder {
 
 	private sessionId = 0;
 
+	public get cameraStarted(): boolean {
+		return this._cameraStarted;
+	}
+
+	private setCameraStarted(value: boolean) {
+		if (this._cameraStarted === value) {
+			return;
+		}
+		this._cameraStarted = value;
+		this.emit('cameraStartedChange', value);
+	}
+
 	public getSupportedMimeTypes() {
 		if (window.MediaRecorder.isTypeSupported('video/webm')) {
 			return 'video/webm; codecs=vp8,opus';
@@ -71,12 +86,11 @@ class VideoRecorder {
 		this.mediaRecorder = new MediaRecorder(this.stream, { mimeType: this.getSupportedMimeTypes() });
 		this.mediaRecorder.ondataavailable = (blobev) => {
 			this.chunks.push(blobev.data);
-			if (!this.recordingAvailable.get()) {
-				return this.recordingAvailable.set(true);
+			if (!this.recordingAvailable) {
+				this.recordingAvailable = true;
 			}
 		};
 		this.mediaRecorder.start();
-		return this.recording.set(true);
 	}
 
 	private stopStreamTracks(stream: MediaStream) {
@@ -109,7 +123,7 @@ class VideoRecorder {
 		}
 
 		this.started = true;
-		return this.cameraStarted.set(true);
+		this.setCameraStarted(true);
 	}
 
 	public stop(cb?: (blob: Blob) => void) {
@@ -128,8 +142,8 @@ class VideoRecorder {
 
 		const wasStarted = this.started;
 		this.started = false;
-		this.cameraStarted.set(false);
-		this.recordingAvailable.set(false);
+		this.setCameraStarted(false);
+		this.recordingAvailable = false;
 
 		if (cb && this.chunks && wasStarted) {
 			const blob = new Blob(this.chunks);
@@ -141,12 +155,11 @@ class VideoRecorder {
 	}
 
 	public stopRecording() {
-		if (!this.started || !this.recording || !this.mediaRecorder) {
+		if (!this.started || !this.mediaRecorder) {
 			return;
 		}
 
 		this.mediaRecorder.stop();
-		this.recording.set(false);
 		delete this.mediaRecorder;
 	}
 }
@@ -154,3 +167,9 @@ class VideoRecorder {
 const instance = new VideoRecorder();
 
 export { instance as VideoRecorder };
+
+export const useVideoRecorderCameraStarted = (): boolean =>
+	useSyncExternalStore(
+		useCallback((onStoreChange) => instance.on('cameraStartedChange', onStoreChange), []),
+		() => instance.cameraStarted,
+	);
diff --git a/apps/meteor/client/apps/gameCenter/GameCenterInvitePlayersModal.tsx b/apps/meteor/client/apps/gameCenter/GameCenterInvitePlayersModal.tsx
index e40afaf35f438..e3a6f13271d01 100644
--- a/apps/meteor/client/apps/gameCenter/GameCenterInvitePlayersModal.tsx
+++ b/apps/meteor/client/apps/gameCenter/GameCenterInvitePlayersModal.tsx
@@ -1,7 +1,7 @@
 import type { IUser } from '@rocket.chat/core-typings';
 import { Box } from '@rocket.chat/fuselage';
+import { Random } from '@rocket.chat/random';
 import { GenericModal } from '@rocket.chat/ui-client';
-import { Tracker } from 'meteor/tracker';
 import type { ReactElement } from 'react';
 import { useState } from 'react';
 import { useTranslation } from 'react-i18next';
@@ -34,19 +34,13 @@ const GameCenterInvitePlayersModal = ({ game, onClose }: IGameCenterInvitePlayer
 
 			roomCoordinator.openRouteLink(result.t, result);
 
-			Tracker.autorun((c) => {
-				if (openedRoom !== result.rid) {
-					return;
-				}
-
+			if (openedRoom === result.rid) {
 				callWithErrorHandling('sendMessage', {
 					_id: Random.id(),
 					rid: result.rid,
 					msg: t('Apps_Game_Center_Play_Game_Together', { name }),
 				});
-
-				c.stop();
-			});
+			}
 			onClose();
 		} catch (err) {
 			console.warn(err);
diff --git a/apps/meteor/client/components/message/toolbar/items/actions/ReactionMessageAction.tsx b/apps/meteor/client/components/message/toolbar/items/actions/ReactionMessageAction.tsx
index 6ce3dc1be51d6..f206df360e76a 100644
--- a/apps/meteor/client/components/message/toolbar/items/actions/ReactionMessageAction.tsx
+++ b/apps/meteor/client/components/message/toolbar/items/actions/ReactionMessageAction.tsx
@@ -6,12 +6,11 @@ import {
 	type IRoom,
 	type ISubscription,
 } from '@rocket.chat/core-typings';
-import { useUser, useEndpoint } from '@rocket.chat/ui-contexts';
-import { useCallback } from 'react';
+import { useUser, useEndpoint, usePermission } from '@rocket.chat/ui-contexts';
+import { useMemo } from 'react';
 import { useTranslation } from 'react-i18next';
 
 import { useEmojiPickerData } from '../../../../../contexts/EmojiPickerContext';
-import { useReactiveValue } from '../../../../../hooks/useReactiveValue';
 import { roomCoordinator } from '../../../../../lib/rooms/roomCoordinator';
 import EmojiElement from '../../../../../views/composer/EmojiPicker/EmojiElement';
 import { useChat } from '../../../../../views/room/contexts/ChatContext';
@@ -33,8 +32,10 @@ const ReactionMessageAction = ({ message, room, subscription }: ReactionMessageA
 	const isFederated = room && isRoomFederated(room);
 	const isFederationBlocked = isFederated && !isRoomNativeFederated(room);
 
-	const enabled = useReactiveValue(
-		useCallback(() => {
+	// depend on post-readonly so readOnly re-evaluates when the permission toggles at runtime.
+	const postReadOnly = usePermission('post-readonly', room._id);
+	const enabled = useMemo(
+		() => {
 			if (isFederationBlocked) {
 				return false;
 			}
@@ -48,7 +49,9 @@ const ReactionMessageAction = ({ message, room, subscription }: ReactionMessageA
 			}
 
 			return true;
-		}, [chat, room, subscription, message.private, user, isFederationBlocked]),
+		},
+		// eslint-disable-next-line react-hooks/exhaustive-deps
+		[chat, room, subscription, message.private, user, isFederationBlocked, postReadOnly],
 	);
 
 	if (!enabled) {
diff --git a/apps/meteor/client/definitions/IOAuthProvider.ts b/apps/meteor/client/definitions/IOAuthProvider.ts
index 00bc3be2b0408..291f2b1ab68cd 100644
--- a/apps/meteor/client/definitions/IOAuthProvider.ts
+++ b/apps/meteor/client/definitions/IOAuthProvider.ts
@@ -1,9 +1,22 @@
-import type { Meteor } from 'meteor/meteor';
+// Shape mirrors @types/meteor's Meteor.LoginWithExternalServiceOptions —
+// the boxed Boolean type is intentional so this stays structurally
+// compatible with existing oauth.ts call sites still typed against
+// Meteor.LoginWithExternalServiceOptions.
+/* eslint-disable @typescript-eslint/no-wrapper-object-types */
+export type LoginWithExternalServiceOptions = {
+	requestPermissions?: readonly string[] | undefined;
+	requestOfflineToken?: Boolean | undefined;
+	forceApprovalPrompt?: Boolean | undefined;
+	redirectUrl?: string | undefined;
+	loginHint?: string | undefined;
+	loginStyle?: string | undefined;
+};
+/* eslint-enable @typescript-eslint/no-wrapper-object-types */
 
 export interface IOAuthProvider {
 	readonly name: string;
 	requestCredential(
-		options: Meteor.LoginWithExternalServiceOptions | undefined,
+		options: LoginWithExternalServiceOptions | undefined,
 		credentialRequestCompleteCallback: (credentialTokenOrError?: string | Error) => void,
 	): void;
 }
diff --git a/apps/meteor/client/importPackages.ts b/apps/meteor/client/importPackages.ts
index 6ec3976093bc5..80901839f7ed5 100644
--- a/apps/meteor/client/importPackages.ts
+++ b/apps/meteor/client/importPackages.ts
@@ -23,4 +23,3 @@ import '../app/slashcommands-unarchiveroom/client';
 import '../app/wordpress/client';
 import '../app/utils/client';
 import '../app/ui-utils/client';
-import '../app/reactions/client';
diff --git a/apps/meteor/client/lib/chats/flows/processSetReaction.ts b/apps/meteor/client/lib/chats/flows/processSetReaction.ts
index 1478320ef3e0b..74e28efa937d7 100644
--- a/apps/meteor/client/lib/chats/flows/processSetReaction.ts
+++ b/apps/meteor/client/lib/chats/flows/processSetReaction.ts
@@ -1,6 +1,7 @@
 import type { IMessage } from '@rocket.chat/core-typings';
 
 import { emoji } from '../../../../app/emoji/client';
+import { runOptimisticSetReaction } from '../../../../app/reactions/client/methods/setReaction';
 import { callWithErrorHandling } from '../../utils/callWithErrorHandling';
 import type { ChatAPI } from '../ChatAPI';
 
@@ -22,6 +23,7 @@ export const processSetReaction = async (chat: ChatAPI, { msg }: Pick<IMessage,
 	}
 
 	chat.composer?.clear();
+	runOptimisticSetReaction(reaction, lastMessage._id);
 	await callWithErrorHandling('setReaction', reaction, lastMessage._id);
 	return true;
 };
diff --git a/apps/meteor/client/lib/chats/flows/sendMessage.ts b/apps/meteor/client/lib/chats/flows/sendMessage.ts
index e2ad4962a851d..1984b999f400d 100644
--- a/apps/meteor/client/lib/chats/flows/sendMessage.ts
+++ b/apps/meteor/client/lib/chats/flows/sendMessage.ts
@@ -1,5 +1,6 @@
 import type { IMessage } from '@rocket.chat/core-typings';
 
+import { runOptimisticSendMessage } from '../../../../app/lib/client/methods/sendMessage';
 import { sdk } from '../../../../app/utils/client/lib/SDKClient';
 import { t } from '../../../../app/utils/lib/i18n';
 import { closeUnclosedCodeBlock } from '../../../../lib/utils/closeUnclosedCodeBlock';
@@ -44,6 +45,7 @@ const process = async (chat: ChatAPI, message: IMessage, previewUrls?: string[],
 	}
 
 	chat.composer?.clear();
+	await runOptimisticSendMessage(message);
 	await sdk.call('sendMessage', message, previewUrls);
 
 	// after the request is complete we can go ahead and mark as sent
diff --git a/apps/meteor/client/lib/chats/readStateManager.ts b/apps/meteor/client/lib/chats/readStateManager.ts
index f464093b79476..e474fe67f1925 100644
--- a/apps/meteor/client/lib/chats/readStateManager.ts
+++ b/apps/meteor/client/lib/chats/readStateManager.ts
@@ -138,7 +138,7 @@ export class ReadStateManager extends Emitter {
 			return;
 		}
 		// if there are unloaded unread messages, don't mark as read
-		if (RoomHistoryManager.getRoom(this.rid).unreadNotLoaded.get() > 0) {
+		if (RoomHistoryManager.getRoom(this.rid).unreadNotLoaded > 0) {
 			return;
 		}
 
@@ -160,7 +160,7 @@ export class ReadStateManager extends Emitter {
 		}
 
 		return sdk.rest.post('/v1/subscriptions.read', { rid: this.rid }).then(() => {
-			RoomHistoryManager.getRoom(this.rid).unreadNotLoaded.set(0);
+			RoomHistoryManager.updateRoom(this.rid, { unreadNotLoaded: 0 });
 		});
 	}
 }
diff --git a/apps/meteor/client/lib/rooms/roomCoordinator.tsx b/apps/meteor/client/lib/rooms/roomCoordinator.tsx
index 54b0cf2145f5a..64a68752eef8e 100644
--- a/apps/meteor/client/lib/rooms/roomCoordinator.tsx
+++ b/apps/meteor/client/lib/rooms/roomCoordinator.tsx
@@ -1,6 +1,5 @@
 import type { IRoom, RoomType, IUser, AtLeast, ValueOf, ISubscription } from '@rocket.chat/core-typings';
 import type { RouteName } from '@rocket.chat/ui-contexts';
-import { Meteor } from 'meteor/meteor';
 
 import { hasPermission } from '../../../app/authorization/client';
 import type {
@@ -203,12 +202,13 @@ class RoomCoordinatorClient extends RoomCoordinator {
 			return false;
 		}
 
-		return Meteor.absoluteUrl(
+		return new URL(
 			router.buildRoutePath({
 				name: config.route.name,
 				params: routeData,
 			}),
-		);
+			__meteor_runtime_config__.ROOT_URL,
+		).toString();
 	}
 
 	public isRouteNameKnown(routeName: string): boolean {
diff --git a/apps/meteor/client/lib/utils/getConfig.ts b/apps/meteor/client/lib/utils/getConfig.ts
index 0c78cf2555a19..1c4c1ff6dc194 100644
--- a/apps/meteor/client/lib/utils/getConfig.ts
+++ b/apps/meteor/client/lib/utils/getConfig.ts
@@ -1,9 +1,15 @@
-import { Meteor } from 'meteor/meteor';
+const readLocalStorage = (key: string): string | null => {
+	try {
+		return window.localStorage.getItem(key);
+	} catch {
+		return null;
+	}
+};
 
 export const getConfig = <T>(key: string, defaultValue?: T): string | null | T => {
 	const searchParams = new URLSearchParams(window.location.search);
 
-	const storedItem = searchParams.get(key) || Meteor._localStorage.getItem(`rc-config-${key}`);
+	const storedItem = searchParams.get(key) || readLocalStorage(`rc-config-${key}`);
 
 	return storedItem ?? defaultValue ?? null;
 };
diff --git a/apps/meteor/client/lib/utils/timeAgo.ts b/apps/meteor/client/lib/utils/timeAgo.ts
index 2826a218d98f8..0889a3e6f0439 100644
--- a/apps/meteor/client/lib/utils/timeAgo.ts
+++ b/apps/meteor/client/lib/utils/timeAgo.ts
@@ -1,5 +1,3 @@
-import { Tracker } from 'meteor/tracker';
-
 import { getUserPreference } from '../../../app/utils/client';
 import { t } from '../../../app/utils/lib/i18n';
 import { settings } from '../settings';
@@ -9,7 +7,7 @@ import { formatTimeAgo } from './dateFormat';
 const dayFormat = ['h:mm A', 'H:mm'];
 
 export const timeAgo = (date: string | Date | number) => {
-	const clockMode = Tracker.nonreactive(() => getUserPreference(getUserId(), 'clockMode', false) as number | boolean);
+	const clockMode = getUserPreference(getUserId(), 'clockMode', false) as number | boolean;
 	const messageTimeFormat = settings.peek('Message_TimeFormat');
 	const sameDay = (typeof clockMode === 'number' ? dayFormat[clockMode - 1] : undefined) || messageTimeFormat;
 
diff --git a/apps/meteor/client/meteor/overrides/oauthRedirectUri.ts b/apps/meteor/client/meteor/overrides/oauthRedirectUri.ts
index 23f53acfe1d77..c9900ff69a417 100644
--- a/apps/meteor/client/meteor/overrides/oauthRedirectUri.ts
+++ b/apps/meteor/client/meteor/overrides/oauthRedirectUri.ts
@@ -1,3 +1,6 @@
+// TODO: remove this override together with the Meteor auth/DDP layer — it
+// monkey-patches meteor/oauth for backwards compatibility with pre-2.3
+// clients. Once Meteor's OAuth stack is gone, this file goes with it.
 import { OAuth } from 'meteor/oauth';
 
 declare module 'meteor/oauth' {
diff --git a/apps/meteor/client/meteor/overrides/userAndUsers.ts b/apps/meteor/client/meteor/overrides/userAndUsers.ts
index aa240aeb00042..ddcaef32a34c3 100644
--- a/apps/meteor/client/meteor/overrides/userAndUsers.ts
+++ b/apps/meteor/client/meteor/overrides/userAndUsers.ts
@@ -1,3 +1,10 @@
+// TODO: remove this override together with the Meteor webapp/DDP/Accounts layer —
+// it bridges Meteor's Accounts.connection userId reactive source to the Zustand
+// userIdStore and keeps Meteor.userId / Meteor.user / Meteor.users pointing at
+// the local Zustand collection. Naively replacing Tracker.autorun with
+// Accounts.onLogin/onLogout breaks callers (e.g. UserProvider's logoutCleanUp)
+// that read userIdStore from within other onLogout callbacks and depend on the
+// async Tracker.flush ordering to still see a truthy uid.
 import { Accounts } from 'meteor/accounts-base';
 import { Meteor } from 'meteor/meteor';
 import { Tracker } from 'meteor/tracker';
diff --git a/apps/meteor/client/meteor/startup/absoluteUrl.ts b/apps/meteor/client/meteor/startup/absoluteUrl.ts
index 8e2578cad8b7b..3566e8f41a443 100644
--- a/apps/meteor/client/meteor/startup/absoluteUrl.ts
+++ b/apps/meteor/client/meteor/startup/absoluteUrl.ts
@@ -1,3 +1,6 @@
+// TODO: remove this file together with the Meteor webapp/DDP layer — it only
+// exists to patch Meteor.absoluteUrl's rootUrl, which no longer has a caller
+// once DDP is gone.
 import { Meteor } from 'meteor/meteor';
 
 import { baseURI } from '../../lib/baseURI';
diff --git a/apps/meteor/client/providers/SessionProvider.tsx b/apps/meteor/client/providers/SessionProvider.tsx
index 00d33729bad9a..0508d172fd0c9 100644
--- a/apps/meteor/client/providers/SessionProvider.tsx
+++ b/apps/meteor/client/providers/SessionProvider.tsx
@@ -1,13 +1,21 @@
+import { Emitter } from '@rocket.chat/emitter';
 import { SessionContext } from '@rocket.chat/ui-contexts';
-import { Session } from 'meteor/session';
 import type { ReactNode } from 'react';
 
-import { createReactiveSubscriptionFactory } from '../lib/createReactiveSubscriptionFactory';
+const store = new Map<string, unknown>();
+const emitter = new Emitter();
 
 const contextValue = {
-	query: createReactiveSubscriptionFactory<unknown>((name) => Session.get(name)),
+	query: (name: string): [subscribe: (onStoreChange: () => void) => () => void, getSnapshot: () => unknown] => [
+		(onStoreChange) => emitter.on(name, onStoreChange),
+		() => store.get(name),
+	],
 	dispatch: (name: string, value: unknown): void => {
-		Session.set(name, value);
+		if (store.has(name) && store.get(name) === value) {
+			return;
+		}
+		store.set(name, value);
+		emitter.emit(name);
 	},
 };
 
diff --git a/apps/meteor/client/startup/incomingMessages.ts b/apps/meteor/client/startup/incomingMessages.ts
index ac840725e9bf4..1301dee578672 100644
--- a/apps/meteor/client/startup/incomingMessages.ts
+++ b/apps/meteor/client/startup/incomingMessages.ts
@@ -1,35 +1,32 @@
 import type { IMessage } from '@rocket.chat/core-typings';
-import { Meteor } from 'meteor/meteor';
 
 import { sdk } from '../../app/utils/client/lib/SDKClient';
 import { onLoggedIn } from '../lib/loggedIn';
 import { getUserId } from '../lib/user';
 import { Messages } from '../stores';
 
-Meteor.startup(() => {
-	onLoggedIn(() => {
-		// Only event I found triggers this is from ephemeral messages
-		// Other types of messages come from another stream
-		return sdk.stream('notify-user', [`${getUserId()}/message`], (msg: IMessage) => {
-			msg.u = msg.u || { username: 'rocket.cat' };
-			msg.private = true;
+onLoggedIn(() => {
+	// Only event I found triggers this is from ephemeral messages
+	// Other types of messages come from another stream
+	return sdk.stream('notify-user', [`${getUserId()}/message`], (msg: IMessage) => {
+		msg.u = msg.u || { username: 'rocket.cat' };
+		msg.private = true;
 
-			return Messages.state.store(msg);
-		});
+		return Messages.state.store(msg);
 	});
+});
 
-	onLoggedIn(() => {
-		return sdk.stream('notify-user', [`${getUserId()}/subscriptions-changed`], (_action, sub) => {
+onLoggedIn(() => {
+	return sdk.stream('notify-user', [`${getUserId()}/subscriptions-changed`], (_action, sub) => {
+		Messages.state.update(
+			(record) => record.rid === sub.rid && ('ignored' in sub && sub.ignored ? !sub.ignored.includes(record.u._id) : 'ignored' in record),
+			({ ignored: _, ...record }) => record,
+		);
+		if ('ignored' in sub && sub.ignored) {
 			Messages.state.update(
-				(record) => record.rid === sub.rid && ('ignored' in sub && sub.ignored ? !sub.ignored.includes(record.u._id) : 'ignored' in record),
-				({ ignored: _, ...record }) => record,
+				(record) => record.rid === sub.rid && record.t !== 'command' && (sub.ignored?.includes(record.u._id) ?? false),
+				(record) => ({ ...record, ignored: true }),
 			);
-			if ('ignored' in sub && sub.ignored) {
-				Messages.state.update(
-					(record) => record.rid === sub.rid && record.t !== 'command' && (sub.ignored?.includes(record.u._id) ?? false),
-					(record) => ({ ...record, ignored: true }),
-				);
-			}
-		});
+		}
 	});
 });
diff --git a/apps/meteor/client/startup/roles.ts b/apps/meteor/client/startup/roles.ts
index de1121d25d69d..8120ef06a518c 100644
--- a/apps/meteor/client/startup/roles.ts
+++ b/apps/meteor/client/startup/roles.ts
@@ -1,40 +1,40 @@
 import type { IRole } from '@rocket.chat/core-typings';
-import { Meteor } from 'meteor/meteor';
-import { Tracker } from 'meteor/tracker';
 
 import { sdk } from '../../app/utils/client/lib/SDKClient';
 import { onLoggedIn } from '../lib/loggedIn';
-import { watchUserId } from '../meteor/user';
+import { userIdStore } from '../lib/user';
 import { Roles } from '../stores';
 
-Meteor.startup(() => {
-	onLoggedIn(async () => {
-		const { roles } = await sdk.rest.get('/v1/roles.list');
-		// if a role is checked before this collection is populated, it will return undefined
-		Roles.state.replaceAll(roles);
-	});
-
-	type ClientAction = 'inserted' | 'updated' | 'removed' | 'changed';
+onLoggedIn(async () => {
+	const { roles } = await sdk.rest.get('/v1/roles.list');
+	// if a role is checked before this collection is populated, it will return undefined
+	Roles.state.replaceAll(roles);
+});
 
-	const events: Record<string, ((role: IRole & { type?: ClientAction }) => void) | undefined> = {
-		changed: (role) => {
-			delete role.type;
-			Roles.state.store(role);
-		},
-		removed: (role) => {
-			Roles.state.delete(role._id);
-		},
-	};
+type ClientAction = 'inserted' | 'updated' | 'removed' | 'changed';
 
-	Tracker.autorun((c) => {
-		if (!watchUserId()) return;
+const events: Record<string, ((role: IRole & { type?: ClientAction }) => void) | undefined> = {
+	changed: (role) => {
+		delete role.type;
+		Roles.state.store(role);
+	},
+	removed: (role) => {
+		Roles.state.delete(role._id);
+	},
+};
 
-		Tracker.afterFlush(() => {
-			sdk.stream('roles', ['roles'], (role) => {
-				events[role.type]?.(role);
-			});
-		});
+const subscribeToRolesStream = () => {
+	sdk.stream('roles', ['roles'], (role) => {
+		events[role.type]?.(role);
+	});
+};
 
-		c.stop();
+if (userIdStore.getState()) {
+	subscribeToRolesStream();
+} else {
+	const unsubscribe = userIdStore.subscribe((uid) => {
+		if (!uid) return;
+		unsubscribe();
+		subscribeToRolesStream();
 	});
-});
+}
diff --git a/apps/meteor/client/startup/startup.ts b/apps/meteor/client/startup/startup.ts
index e9568ae7e2dea..10bcbd8171cf9 100644
--- a/apps/meteor/client/startup/startup.ts
+++ b/apps/meteor/client/startup/startup.ts
@@ -1,43 +1,56 @@
 import type { UserStatus } from '@rocket.chat/core-typings';
-import { Meteor } from 'meteor/meteor';
-import { Tracker } from 'meteor/tracker';
+import { Accounts } from 'meteor/accounts-base';
 
 import 'highlight.js/styles/github.css';
 import { sdk } from '../../app/utils/client/lib/SDKClient';
-import { synchronizeUserData, removeLocalUserData } from '../lib/userData';
+import { onLoggedIn } from '../lib/loggedIn';
+import { userIdStore } from '../lib/user';
+import { removeLocalUserData, synchronizeUserData } from '../lib/userData';
 import { fireGlobalEvent } from '../lib/utils/fireGlobalEvent';
-import { watchUserId } from '../meteor/user';
-
-Meteor.startup(() => {
-	let status: UserStatus | undefined = undefined;
-	Tracker.autorun(async () => {
-		const uid = watchUserId();
-		if (!uid) {
-			removeLocalUserData();
-			return;
-		}
-
-		if (!Meteor.status().connected) {
-			return;
-		}
-
-		if (Meteor.loggingIn()) {
-			return;
-		}
-
-		const user = await synchronizeUserData(uid);
-		if (!user) {
-			return;
-		}
-
-		const utcOffset = -new Date().getTimezoneOffset() / 60;
-		if (user.utcOffset !== utcOffset) {
-			sdk.call('userSetUtcOffset', utcOffset);
-		}
-
-		if (user.status !== status) {
-			status = user.status;
-			fireGlobalEvent('status-changed', status);
-		}
-	});
+import { Users } from '../stores';
+
+let status: UserStatus | undefined = undefined;
+
+const emitStatusChange = (next: UserStatus | undefined) => {
+	if (next === status) return;
+	status = next;
+	fireGlobalEvent('status-changed', status);
+};
+
+onLoggedIn(async () => {
+	const uid = userIdStore.getState();
+	if (!uid) return;
+
+	const user = await synchronizeUserData(uid);
+	if (!user) return;
+
+	const utcOffset = -new Date().getTimezoneOffset() / 60;
+	if (user.utcOffset !== utcOffset) {
+		sdk.call('userSetUtcOffset', utcOffset);
+	}
+
+	emitStatusChange(user.status);
 });
+
+Users.use.subscribe(() => {
+	const uid = userIdStore.getState();
+	if (!uid) return;
+	const user = Users.use.getState().get(uid);
+	if (!user) return;
+	emitStatusChange(user.status);
+});
+
+Accounts.onLogout(() => {
+	removeLocalUserData();
+	status = undefined;
+});
+
+// Session-resume failure (expired stored token on page load): Meteor has already
+// cleared Meteor.loginToken before this module runs, userId stays null, and no
+// Accounts.onLogout callback fires for this scenario. Detect via the combination
+// of missing token and missing uid at module init and clean up residual keys
+// (e.g. E2EE public_key / private_key). Do NOT subscribe to userIdStore for this —
+// the valid-session resume path is async and would clobber a valid token mid-flight.
+if (!userIdStore.getState() && localStorage.getItem('Meteor.loginToken') === null) {
+	removeLocalUserData();
+}
diff --git a/apps/meteor/client/startup/streamMessage/autotranslate.ts b/apps/meteor/client/startup/streamMessage/autotranslate.ts
index c24b4e6dc310e..98913a16191db 100644
--- a/apps/meteor/client/startup/streamMessage/autotranslate.ts
+++ b/apps/meteor/client/startup/streamMessage/autotranslate.ts
@@ -1,23 +1,28 @@
 import { clientCallbacks } from '@rocket.chat/ui-client';
-import { Meteor } from 'meteor/meteor';
-import { Tracker } from 'meteor/tracker';
 
 import { hasPermission } from '../../../app/authorization/client';
+import { PermissionsCachedStore } from '../../cachedStores';
 import { settings } from '../../lib/settings';
+import { Users } from '../../stores';
 
-Meteor.startup(() => {
-	Tracker.autorun(() => {
-		const isEnabled = settings.watch('AutoTranslate_Enabled') && hasPermission('auto-translate');
+const STREAM_HANDLER_ID = 'autotranslate-stream';
 
-		if (!isEnabled) {
-			clientCallbacks.remove('streamMessage', 'autotranslate-stream');
-			return;
-		}
+const applyAutoTranslateStreamHandler = () => {
+	const isEnabled = settings.peek('AutoTranslate_Enabled') && hasPermission('auto-translate');
 
-		import('../../../app/autotranslate/client').then(({ createAutoTranslateMessageStreamHandler }) => {
-			const streamMessage = createAutoTranslateMessageStreamHandler();
-			clientCallbacks.remove('streamMessage', 'autotranslate-stream');
-			clientCallbacks.add('streamMessage', streamMessage, clientCallbacks.priority.HIGH - 3, 'autotranslate-stream');
-		});
+	if (!isEnabled) {
+		clientCallbacks.remove('streamMessage', STREAM_HANDLER_ID);
+		return;
+	}
+
+	void import('../../../app/autotranslate/client').then(({ createAutoTranslateMessageStreamHandler }) => {
+		const streamMessage = createAutoTranslateMessageStreamHandler();
+		clientCallbacks.remove('streamMessage', STREAM_HANDLER_ID);
+		clientCallbacks.add('streamMessage', streamMessage, clientCallbacks.priority.HIGH - 3, STREAM_HANDLER_ID);
 	});
-});
+};
+
+applyAutoTranslateStreamHandler();
+settings.observe('AutoTranslate_Enabled', applyAutoTranslateStreamHandler);
+PermissionsCachedStore.useReady.subscribe(applyAutoTranslateStreamHandler);
+Users.use.subscribe(applyAutoTranslateStreamHandler);
diff --git a/apps/meteor/client/views/composer/VideoMessageRecorder/VideoMessageRecorder.tsx b/apps/meteor/client/views/composer/VideoMessageRecorder/VideoMessageRecorder.tsx
index 5952c35da15e3..6d59550e0ec0d 100644
--- a/apps/meteor/client/views/composer/VideoMessageRecorder/VideoMessageRecorder.tsx
+++ b/apps/meteor/client/views/composer/VideoMessageRecorder/VideoMessageRecorder.tsx
@@ -7,7 +7,7 @@ import type { AllHTMLAttributes, RefObject } from 'react';
 import { useRef, useEffect, useState } from 'react';
 
 import { UserAction, USER_ACTIVITIES } from '../../../../app/ui/client/lib/UserAction';
-import { VideoRecorder } from '../../../../app/ui/client/lib/recorderjs/videoRecorder';
+import { VideoRecorder, useVideoRecorderCameraStarted } from '../../../../app/ui/client/lib/recorderjs/videoRecorder';
 import { useChat } from '../../room/contexts/ChatContext';
 
 type VideoMessageRecorderProps = {
@@ -45,7 +45,8 @@ const VideoMessageRecorder = ({ rid, tmid, reference }: VideoMessageRecorderProp
 	const [recordingState, setRecordingState] = useState<'idle' | 'loading' | 'recording'>('idle');
 	const [recordingInterval, setRecordingInterval] = useState<ReturnType<typeof setInterval> | null>(null);
 	const isRecording = recordingState === 'recording';
-	const sendButtonDisabled = !(VideoRecorder.cameraStarted.get() && !(recordingState === 'recording'));
+	const cameraStarted = useVideoRecorderCameraStarted();
+	const sendButtonDisabled = !(cameraStarted && !isRecording);
 
 	const chat = useChat();
 
diff --git a/apps/meteor/client/views/omnichannel/businessHours/useIsSingleBusinessHours.ts b/apps/meteor/client/views/omnichannel/businessHours/useIsSingleBusinessHours.ts
index 67c7877ce34df..29bc09cbeca6d 100644
--- a/apps/meteor/client/views/omnichannel/businessHours/useIsSingleBusinessHours.ts
+++ b/apps/meteor/client/views/omnichannel/businessHours/useIsSingleBusinessHours.ts
@@ -1,7 +1,5 @@
-import { useEffectEvent } from '@rocket.chat/fuselage-hooks';
-
 import { businessHourManager } from '../../../../app/livechat/client/views/app/business-hours/BusinessHours';
-import { useReactiveValue } from '../../../hooks/useReactiveValue';
 
-export const useIsSingleBusinessHours = () =>
-	useReactiveValue(useEffectEvent(() => businessHourManager.getTemplate())) === 'livechatBusinessHoursForm';
+// businessHourManager holds a single behavior instance with no reactive store — the previous
+// useReactiveValue wrapper never actually re-ran, so this is a plain read.
+export const useIsSingleBusinessHours = () => businessHourManager.getTemplate() === 'livechatBusinessHoursForm';
diff --git a/apps/meteor/client/views/room/E2EESetup/RoomE2EESetup.tsx b/apps/meteor/client/views/room/E2EESetup/RoomE2EESetup.tsx
index 68635721f2f52..cd95b23156a44 100644
--- a/apps/meteor/client/views/room/E2EESetup/RoomE2EESetup.tsx
+++ b/apps/meteor/client/views/room/E2EESetup/RoomE2EESetup.tsx
@@ -1,4 +1,3 @@
-import { Accounts } from 'meteor/accounts-base';
 import { useCallback } from 'react';
 import { useTranslation } from 'react-i18next';
 
@@ -16,7 +15,7 @@ const RoomE2EESetup = () => {
 	const e2eRoomState = useE2EERoomState(room._id);
 
 	const { t } = useTranslation();
-	const randomPassword = Accounts.storageLocation.getItem('e2e.randomPassword');
+	const randomPassword = localStorage.getItem('e2e.randomPassword');
 
 	const onSavePassword = useCallback(() => {
 		if (!randomPassword) {
diff --git a/apps/meteor/client/views/room/body/hooks/useFileUploadDropTarget.ts b/apps/meteor/client/views/room/body/hooks/useFileUploadDropTarget.ts
index 0a5ab4c11ab91..c4aedcadb940f 100644
--- a/apps/meteor/client/views/room/body/hooks/useFileUploadDropTarget.ts
+++ b/apps/meteor/client/views/room/body/hooks/useFileUploadDropTarget.ts
@@ -1,10 +1,9 @@
 import { useEffectEvent } from '@rocket.chat/fuselage-hooks';
-import { useSetting, useTranslation, useUser } from '@rocket.chat/ui-contexts';
+import { usePermission, useSetting, useTranslation, useUser } from '@rocket.chat/ui-contexts';
 import type { DragEvent, ReactNode } from 'react';
-import { useCallback, useMemo, useSyncExternalStore } from 'react';
+import { useMemo, useSyncExternalStore } from 'react';
 
 import { useDropTarget } from './useDropTarget';
-import { useReactiveValue } from '../../../../hooks/useReactiveValue';
 import { roomCoordinator } from '../../../../lib/rooms/roomCoordinator';
 import { useIsRoomOverMacLimit } from '../../../omnichannel/hooks/useIsRoomOverMacLimit';
 import { useChat } from '../../contexts/ChatContext';
@@ -30,8 +29,11 @@ export const useFileUploadDropTarget = (): readonly [
 
 	const fileUploadEnabled = useSetting('FileUpload_Enabled', true);
 	const user = useUser();
-	const fileUploadAllowedForUser = useReactiveValue(
-		useCallback(() => !roomCoordinator.readOnly(room, { username: user?.username }), [room, user?.username]),
+	const postReadOnly = usePermission('post-readonly', room._id);
+	const fileUploadAllowedForUser = useMemo(
+		() => !roomCoordinator.readOnly(room, { username: user?.username }),
+		// eslint-disable-next-line react-hooks/exhaustive-deps
+		[room, user?.username, postReadOnly],
 	);
 
 	const chat = useChat();
diff --git a/apps/meteor/client/views/room/body/hooks/useUnreadMessages.ts b/apps/meteor/client/views/room/body/hooks/useUnreadMessages.ts
index b30a78e3f9994..d818104ccbc47 100644
--- a/apps/meteor/client/views/room/body/hooks/useUnreadMessages.ts
+++ b/apps/meteor/client/views/room/body/hooks/useUnreadMessages.ts
@@ -1,12 +1,10 @@
 import type { IRoom, ISubscription } from '@rocket.chat/core-typings';
 import { useRouter } from '@rocket.chat/ui-contexts';
-import { Tracker } from 'meteor/tracker';
 import type { Dispatch, MutableRefObject, SetStateAction } from 'react';
 import { useCallback, useEffect, useMemo, useRef, useState } from 'react';
 
-import { RoomHistoryManager } from '../../../../../app/ui-utils/client';
+import { RoomHistoryManager, useRoomHistoryState } from '../../../../../app/ui-utils/client/lib/RoomHistoryManager';
 import { withDebouncing, withThrottling } from '../../../../../lib/utils/highOrderFunctions';
-import { useReactiveValue } from '../../../../hooks/useReactiveValue';
 import { useOpenedRoomUnreadSince } from '../../../../lib/RoomManager';
 import { roomCoordinator } from '../../../../lib/rooms/roomCoordinator';
 import { setMessageJumpQueryStringParameter } from '../../../../lib/utils/setMessageJumpQueryStringParameter';
@@ -19,7 +17,7 @@ interface IUnreadMessages {
 }
 
 const useUnreadMessages = (room: IRoom): readonly [data: IUnreadMessages | undefined, setUnreadCount: Dispatch<SetStateAction<number>>] => {
-	const notLoadedCount = useReactiveValue(useCallback(() => RoomHistoryManager.getRoom(room._id).unreadNotLoaded.get(), [room._id]));
+	const notLoadedCount = useRoomHistoryState(room._id, (state) => state.unreadNotLoaded);
 	const [loadedCount, setLoadedCount] = useState(0);
 
 	const count = useMemo(() => notLoadedCount + loadedCount, [notLoadedCount, loadedCount]);
@@ -64,7 +62,7 @@ export const useHandleUnread = (
 	const handleUnreadBarJumpToButtonClick = useCallback(() => {
 		const rid = room._id;
 		const { firstUnread } = RoomHistoryManager.getRoom(rid);
-		let message = firstUnread?.get();
+		let message = firstUnread;
 		if (!message) {
 			message = findFirstMessage(
 				(record) => record.rid === rid && record.ts.getTime() > (unread?.since.getTime() ?? -Infinity),
@@ -169,7 +167,7 @@ export const useHandleUnread = (
 			wrapper.addEventListener(
 				'scroll',
 				withThrottling({ wait: 300 })(() => {
-					Tracker.afterFlush(() => {
+					queueMicrotask(() => {
 						const lastInvisibleMessageOnScreen = getElementFromPoint(0) || getElementFromPoint(20) || getElementFromPoint(40);
 
 						if (!lastInvisibleMessageOnScreen) {
diff --git a/apps/meteor/client/views/room/composer/hooks/useMessageComposerIsReadOnly.ts b/apps/meteor/client/views/room/composer/hooks/useMessageComposerIsReadOnly.ts
index 974b5b16f539a..9625f8bc389c6 100644
--- a/apps/meteor/client/views/room/composer/hooks/useMessageComposerIsReadOnly.ts
+++ b/apps/meteor/client/views/room/composer/hooks/useMessageComposerIsReadOnly.ts
@@ -1,11 +1,14 @@
 import type { IRoom } from '@rocket.chat/core-typings';
-import { useUser } from '@rocket.chat/ui-contexts';
-import { useCallback } from 'react';
+import { usePermission, useUser } from '@rocket.chat/ui-contexts';
+import { useMemo } from 'react';
 
-import { useReactiveValue } from '../../../../hooks/useReactiveValue';
 import { roomCoordinator } from '../../../../lib/rooms/roomCoordinator';
 
 export const useMessageComposerIsReadOnly = (room: IRoom): boolean => {
 	const user = useUser();
-	return useReactiveValue(useCallback(() => roomCoordinator.readOnly(room, user), [room, user]));
+	// depend on post-readonly so this re-runs when the permission is granted/revoked at runtime;
+	// roomCoordinator.readOnly calls hasPermission internally and returns the up-to-date value.
+	const postReadOnly = usePermission('post-readonly', room._id);
+	// eslint-disable-next-line react-hooks/exhaustive-deps
+	return useMemo(() => roomCoordinator.readOnly(room, user), [room, user, postReadOnly]);
 };
diff --git a/apps/meteor/client/views/room/composer/messageBox/MessageBox.tsx b/apps/meteor/client/views/room/composer/messageBox/MessageBox.tsx
index c653b0a132e55..20b6f94ebcc4e 100644
--- a/apps/meteor/client/views/room/composer/messageBox/MessageBox.tsx
+++ b/apps/meteor/client/views/room/composer/messageBox/MessageBox.tsx
@@ -28,10 +28,10 @@ import { formattingButtons } from '../../../../../app/ui-message/client/messageB
 import { getImageExtensionFromMime } from '../../../../../lib/getImageExtensionFromMime';
 import { useFormatDateAndTime } from '../../../../hooks/useFormatDateAndTime';
 import { useIsFederationEnabled } from '../../../../hooks/useIsFederationEnabled';
-import { useReactiveValue } from '../../../../hooks/useReactiveValue';
 import type { ComposerAPI } from '../../../../lib/chats/ChatAPI';
 import { roomCoordinator } from '../../../../lib/rooms/roomCoordinator';
 import { keyCodes } from '../../../../lib/utils/keyCodes';
+import { Subscriptions } from '../../../../stores';
 import AudioMessageRecorder from '../../../composer/AudioMessageRecorder';
 import VideoMessageRecorder from '../../../composer/VideoMessageRecorder';
 import { useFileUpload } from '../../body/hooks/useFileUpload';
@@ -293,27 +293,28 @@ const MessageBox = ({
 
 	const federationMatrixEnabled = useIsFederationEnabled();
 
-	const canSend = useReactiveValue(
-		useCallback(() => {
-			if (!room.t) {
-				return false;
-			}
+	// canSendMessage directives read from the Subscriptions store, so subscribe to it to re-run on changes
+	// (e.g. user joins/leaves the room). room and federationMatrixEnabled are already React-reactive.
+	const subscribeSubscriptions = useCallback((onStoreChange: () => void) => Subscriptions.use.subscribe(onStoreChange), []);
+	const canSend = useSyncExternalStore(subscribeSubscriptions, () => {
+		if (!room.t) {
+			return false;
+		}
+
+		if (!roomCoordinator.getRoomDirectives(room.t).canSendMessage(room)) {
+			return false;
+		}
 
-			if (!roomCoordinator.getRoomDirectives(room.t).canSendMessage(room)) {
+		if (isRoomFederated(room)) {
+			// we are dropping the non native federation for now
+			if (!isRoomNativeFederated(room)) {
 				return false;
 			}
 
-			if (isRoomFederated(room)) {
-				// we are dropping the non native federation for now
-				if (!isRoomNativeFederated(room)) {
-					return false;
-				}
-
-				return federationMatrixEnabled;
-			}
-			return true;
-		}, [room, federationMatrixEnabled]),
-	);
+			return federationMatrixEnabled;
+		}
+		return true;
+	});
 
 	const sizes = useContentBoxSize(textareaRef);
 
diff --git a/apps/meteor/client/views/room/providers/RoomProvider.tsx b/apps/meteor/client/views/room/providers/RoomProvider.tsx
index 78c76e553779a..d4fb329c54885 100644
--- a/apps/meteor/client/views/room/providers/RoomProvider.tsx
+++ b/apps/meteor/client/views/room/providers/RoomProvider.tsx
@@ -1,6 +1,6 @@
 import type { IRoom } from '@rocket.chat/core-typings';
 import type { ReactNode, ContextType, ReactElement } from 'react';
-import { useMemo, memo, useEffect, useCallback } from 'react';
+import { useMemo, memo, useEffect } from 'react';
 
 import ComposerPopupProvider from './ComposerPopupProvider';
 import RoomToolboxProvider from './RoomToolboxProvider';
@@ -8,10 +8,9 @@ import UserCardProvider from './UserCardProvider';
 import { useRedirectOnSettingsChanged } from './hooks/useRedirectOnSettingsChanged';
 import { useUsersNameChanged } from './hooks/useUsersNameChanged';
 import { UserAction } from '../../../../app/ui/client/lib/UserAction';
-import { RoomHistoryManager } from '../../../../app/ui-utils/client';
+import { useRoomHistoryState } from '../../../../app/ui-utils/client/lib/RoomHistoryManager';
 import { omit } from '../../../../lib/utils/omit';
 import { useFireGlobalEvent } from '../../../hooks/useFireGlobalEvent';
-import { useReactiveValue } from '../../../hooks/useReactiveValue';
 import { RoomManager } from '../../../lib/RoomManager';
 import { roomCoordinator } from '../../../lib/rooms/roomCoordinator';
 import ImageGalleryProvider from '../../../providers/ImageGalleryProvider';
@@ -48,17 +47,9 @@ const RoomProvider = ({ rid, children }: RoomProviderProps): ReactElement => {
 		};
 	}, [room, subscritionFromLocal]);
 
-	const { hasMorePreviousMessages, hasMoreNextMessages, isLoadingMoreMessages } = useReactiveValue(
-		useCallback(() => {
-			const { hasMore, hasMoreNext, isLoading } = RoomHistoryManager.getRoom(rid);
-
-			return {
-				hasMorePreviousMessages: hasMore.get(),
-				hasMoreNextMessages: hasMoreNext.get(),
-				isLoadingMoreMessages: isLoading.get(),
-			};
-		}, [rid]),
-	);
+	const hasMorePreviousMessages = useRoomHistoryState(rid, (state) => state.hasMore);
+	const hasMoreNextMessages = useRoomHistoryState(rid, (state) => state.hasMoreNext);
+	const isLoadingMoreMessages = useRoomHistoryState(rid, (state) => state.isLoading);
 
 	const context = useMemo((): ContextType<typeof RoomContext> => {
 		if (!pseudoRoom) {
diff --git a/apps/meteor/client/views/root/IndexRoute.tsx b/apps/meteor/client/views/root/IndexRoute.tsx
index 90773af044916..32f1526f63ae1 100644
--- a/apps/meteor/client/views/root/IndexRoute.tsx
+++ b/apps/meteor/client/views/root/IndexRoute.tsx
@@ -1,6 +1,5 @@
 import type { RouteName } from '@rocket.chat/ui-contexts';
 import { useRouter, useUser, useUserId } from '@rocket.chat/ui-contexts';
-import { Tracker } from 'meteor/tracker';
 import { useEffect } from 'react';
 
 import PageLoading from './PageLoading';
@@ -16,24 +15,21 @@ const IndexRoute = () => {
 			return;
 		}
 
-		const computation = Tracker.autorun((c) => {
-			setTimeout(async () => {
-				if (user?.defaultRoom) {
-					const room = user.defaultRoom.split('/') as [routeName: RouteName, routeParam: string];
-					router.navigate({
-						name: room[0],
-						params: { name: room[1] },
-						search: router.getSearchParameters(),
-					});
-				} else {
-					router.navigate('/home');
-				}
-			}, 0);
-			c.stop();
-		});
+		const timerId = setTimeout(() => {
+			if (user?.defaultRoom) {
+				const room = user.defaultRoom.split('/') as [routeName: RouteName, routeParam: string];
+				router.navigate({
+					name: room[0],
+					params: { name: room[1] },
+					search: router.getSearchParameters(),
+				});
+			} else {
+				router.navigate('/home');
+			}
+		}, 0);
 
 		return () => {
-			computation.stop();
+			clearTimeout(timerId);
 		};
 	}, [router, uid, user?.defaultRoom]);
 
diff --git a/apps/meteor/client/views/root/hooks/useCorsSSLConfig.ts b/apps/meteor/client/views/root/hooks/useCorsSSLConfig.ts
index c26cb62b7f480..ba3ea5c4ded6f 100644
--- a/apps/meteor/client/views/root/hooks/useCorsSSLConfig.ts
+++ b/apps/meteor/client/views/root/hooks/useCorsSSLConfig.ts
@@ -1,3 +1,6 @@
+// TODO: remove this hook together with the Meteor webapp/DDP layer — it only
+// patches Meteor.absoluteUrl's `secure` default, which has no consumers once
+// Meteor.absoluteUrl is gone.
 import { useSetting } from '@rocket.chat/ui-contexts';
 import { Meteor } from 'meteor/meteor';
 import { useEffect } from 'react';
diff --git a/apps/meteor/client/views/root/hooks/useIframe.ts b/apps/meteor/client/views/root/hooks/useIframe.ts
index c0cfd4cbd678c..b66b9f247fc36 100644
--- a/apps/meteor/client/views/root/hooks/useIframe.ts
+++ b/apps/meteor/client/views/root/hooks/useIframe.ts
@@ -1,8 +1,9 @@
 import { useEffectEvent } from '@rocket.chat/fuselage-hooks';
 import { useLoginWithIframe, useLoginWithToken, useSetting } from '@rocket.chat/ui-contexts';
-import type { Meteor } from 'meteor/meteor';
 import { useCallback, useEffect, useState } from 'react';
 
+type CallbackError = Error & { error?: string | number; reason?: string; details?: unknown };
+
 export const useIframe = () => {
 	const [iframeLoginUrl, setIframeLoginUrl] = useState<string | undefined>(undefined);
 
@@ -62,7 +63,7 @@ export const useIframe = () => {
 			}
 
 			const body = await result.json();
-			loginWithToken(body, async (error: Meteor.Error | Meteor.TypedError | Error | null | undefined) => {
+			loginWithToken(body, async (error: CallbackError | Error | null | undefined) => {
 				if (error) {
 					setIframeLoginUrl(url);
 				} else {