diff --git a/angular.json b/angular.json
index 2ed16994b..907d1a9f5 100644
--- a/angular.json
+++ b/angular.json
@@ -72,6 +72,11 @@
             "production": {
               "baseHref": "",
               "budgets": [
+                {
+                  "type": "initial",
+                  "maximumWarning": "5.5mb",
+                  "maximumError": "6mb"
+                },
                 {
                   "type": "anyComponentStyle",
                   "maximumWarning": "20kb"
@@ -104,6 +109,11 @@
                 "browser": "browser"
               },
               "budgets": [
+                {
+                  "type": "initial",
+                  "maximumWarning": "5.5mb",
+                  "maximumError": "6mb"
+                },
                 {
                   "type": "anyComponentStyle",
                   "maximumWarning": "20kb"
@@ -133,6 +143,11 @@
             "stage": {
               "baseHref": "",
               "budgets": [
+                {
+                  "type": "initial",
+                  "maximumWarning": "5.5mb",
+                  "maximumError": "6mb"
+                },
                 {
                   "type": "anyComponentStyle",
                   "maximumWarning": "20kb"
diff --git a/src/app/app.component.ts b/src/app/app.component.ts
index efcc623f4..77c37b91a 100644
--- a/src/app/app.component.ts
+++ b/src/app/app.component.ts
@@ -230,9 +230,14 @@ export class AppComponent implements OnDestroy, AfterViewInit {
       });
 
     // ! For keyboard shortcuts to work correctly with any layouts (QWERTZ/AZERTY/etc) - user's keyboard layout must be presaved
-    // Connect the service to the utility functions and save the layout
+    // Connect the service to the utility functions
     setKeyboardLayoutService(this._keyboardLayoutService);
-    this._keyboardLayoutService.saveUserLayout();
+    // Defer keyboard layout detection to idle time for better initial load performance
+    if (typeof requestIdleCallback === 'function') {
+      requestIdleCallback(() => this._keyboardLayoutService.saveUserLayout());
+    } else {
+      setTimeout(() => this._keyboardLayoutService.saveUserLayout(), 0);
+    }
   }
 
   skipInitialSync(): void {
diff --git a/src/app/core/startup/startup.service.ts b/src/app/core/startup/startup.service.ts
index 305f99079..a3278d6c7 100644
--- a/src/app/core/startup/startup.service.ts
+++ b/src/app/core/startup/startup.service.ts
@@ -162,11 +162,13 @@ export class StartupService {
   private async _checkIsSingleInstance(): Promise<boolean> {
     const channel = new BroadcastChannel('superProductivityTab');
     let isAnotherInstanceActive = false;
+    let resolved = false;
 
     // 1. Listen for other instances saying "I'm here!"
     const checkListener = (msg: MessageEvent): void => {
       if (msg.data === 'alreadyOpenElsewhere') {
         isAnotherInstanceActive = true;
+        resolved = true;
       }
     };
     channel.addEventListener('message', checkListener);
@@ -174,8 +176,20 @@ export class StartupService {
     // 2. Ask "Is anyone here?"
     channel.postMessage('newTabOpened');
 
-    // 3. Wait a bit for a response
-    await new Promise((resolve) => setTimeout(resolve, 150));
+    // 3. Wait for response with early exit - reduced from 150ms to 50ms
+    // BroadcastChannel is synchronous within the same origin, so 50ms is sufficient
+    await new Promise<void>((resolve) => {
+      const checkInterval = setInterval(() => {
+        if (resolved) {
+          clearInterval(checkInterval);
+          resolve();
+        }
+      }, 10);
+      setTimeout(() => {
+        clearInterval(checkInterval);
+        resolve();
+      }, 50);
+    });
 
     channel.removeEventListener('message', checkListener);
 
diff --git a/src/app/features/metric/metric.component.html b/src/app/features/metric/metric.component.html
index ab563fd4d..2992e942a 100644
--- a/src/app/features/metric/metric.component.html
+++ b/src/app/features/metric/metric.component.html
@@ -68,7 +68,15 @@
   }
 
   <section style="max-width: 880px; margin: auto; margin-top: 32px">
-    <activity-heatmap></activity-heatmap>
+    @defer (on viewport) {
+      <activity-heatmap></activity-heatmap>
+    } @placeholder {
+      <div
+        style="height: 200px; display: flex; align-items: center; justify-content: center"
+      >
+        Loading activity heatmap...
+      </div>
+    }
   </section>
 
   @if (!metricService.hasData()) {
diff --git a/src/main.ts b/src/main.ts
index 8a9392896..36f0e0b5c 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -197,10 +197,28 @@ bootstrapApplication(AppComponent, {
   // Initialize touch fix for Material menus
   initializeMatMenuTouchFix();
 
-  // Register all supported locales
-  Object.keys(LocalesImports).forEach((locale) => {
-    registerLocaleData(LocalesImports[locale], locale);
-  });
+  // Register default locale immediately for fast startup
+  registerLocaleData(LocalesImports[DEFAULT_LANGUAGE], DEFAULT_LANGUAGE);
+
+  // Defer other locales to idle time for better initial load performance
+  if (typeof requestIdleCallback === 'function') {
+    requestIdleCallback(() => {
+      Object.keys(LocalesImports).forEach((locale) => {
+        if (locale !== DEFAULT_LANGUAGE) {
+          registerLocaleData(LocalesImports[locale], locale);
+        }
+      });
+    });
+  } else {
+    // Fallback for browsers without requestIdleCallback
+    setTimeout(() => {
+      Object.keys(LocalesImports).forEach((locale) => {
+        if (locale !== DEFAULT_LANGUAGE) {
+          registerLocaleData(LocalesImports[locale], locale);
+        }
+      });
+    }, 0);
+  }
 
   // TODO make asset caching work for electron