Why am I getting errors while sending notification from firebase

Question

The code for the app in which initializing firebase:

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  runApp(const MyApp());
}

class MyApp extends StatefulWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  @override
  void initState() {
    // TODO: implement initState
    super.initState();

    FirebaseMessaging.instance.getInitialMessage();

    ///foreground notification
    FirebaseMessaging.onMessage.listen((message) {
      if (message.notification != null) {
        print(message.notification!.title);
        print(message.notification!.body);
      }
    });

    ///background & opened notification
    ///tapped on notification
    FirebaseMessaging.onMessageOpenedApp.listen((message) {
      final routeFromMessage = message.data['route'];
      Navigator.of(context).pushNamed(routeFromMessage);
    });

  }

Now if the code worked correctly, it should have navigated me to the respective routed page and printed the notification title and body in the console.

But instead I am getting errors like this:

D/FLTFireMsgReceiver( 9928): broadcast received for message
W/FLTFireMsgService( 9928): A background message could not be handled in Dart as no onBackgroundMessage handler has been registered.
W/FirebaseMessaging( 9928): Missing Default Notification Channel metadata in AndroidManifest. Default value will be used.
E/flutter ( 9928): [ERROR:flutter/lib/ui/ui_dart_state.cc(209)] Unhandled Exception: Navigator operation requested with a context that does not include a Navigator.
E/flutter ( 9928): The context used to push or pop routes from the Navigator must be that of a widget that is a descendant of a Navigator widget.
E/flutter ( 9928): #0      Navigator.of.<anonymous closure>
package:flutter/…/widgets/navigator.dart:2553
E/flutter ( 9928): #1      Navigator.of
package:flutter/…/widgets/navigator.dart:2560
E/flutter ( 9928): #2      _MyAppState.initState.<anonymous closure>
package:note_reminder/main.dart:42
E/flutter ( 9928): #3      _rootRunUnary (dart:async/zone.dart:1434:47)
E/flutter ( 9928): #4      _CustomZone.runUnary (dart:async/zone.dart:1335:19)
E/flutter ( 9928): #5      _CustomZone.runUnaryGuarded (dart:async/zone.dart:1244:7)
E/flutter ( 9928): #6      _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:341:11)
E/flutter ( 9928): #7      _DelayedData.perform (dart:async/stream_impl.dart:591:14)
E/flutter ( 9928): #8      _StreamImplEvents.handleNext (dart:async/stream_impl.dart:706:11)
E/flutter ( 9928): #9      _PendingEvents.schedule.<anonymous closure> (dart:async/stream_impl.dart:663:7)
E/flutter ( 9928): #10     _rootRun (dart:async/zone.dart:1418:47)
E/flutter ( 9928): #11     _CustomZone.run (dart:async/zone.dart:1328:19)
E/flutter ( 9928): #12     _CustomZone.runGuarded (dart:async/zone.dart:1236:7)
E/flutter ( 9928): #13     _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:1276:23)
E/flutter ( 9928): #14     _rootRun (dart:async/zone.dart:1426:13)
E/flutter ( 9928): #15     _CustomZone.run (dart:async/zone.dart:1328:19)
E/flutter ( 9928): #16     _CustomZone.runGuarded (dart:async/zone.dart:1236:7)
E/flutter ( 9928): #17     _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:1276:23)
E/flutter ( 9928): #18     _microtaskLoop (dart:async/schedule_microtask.dart:40:21)
E/flutter ( 9928): #19     _startMicrotaskLoop (dart:async/schedule_microtask.dart:49:5)
E/flutter ( 9928):
I/OpenGLRenderer( 9928): Davey! duration=567777ms; Flags=1, FrameTimelineVsyncId=76328, IntendedVsync=19427849009190, Vsync=19427849009190, InputEventId=0, HandleInputStart=19427850193500, AnimationStart=19427850214100, PerformTraversalsStart=19427851010200, DrawStart=19427851815400, FrameDeadline=19427899009188, FrameInterval=19427850132400, FrameStartTime=16666666, SyncQueued=19427852843800, SyncStart=19427853556300, IssueDrawCommandsStart=19427855478900, SwapBuffers=19427864095600, FrameCompleted=19995626844200, DequeueBufferDuration=7109800, QueueBufferDuration=670800, GpuCompleted=19995626844200, SwapBuffersCompleted=19427873795500, DisplayPresentTime=25614609433559128,

Also note that I am trying to route to a screen that I am using with a custom navbar.

Code of routes:

home: OnBoardingPage(),
      routes: {
        'done': (context) => DonePage(),
        'create': (context) => CreatePage(),
        'history': (context) => HistoryPage(),

Code of my Home Page:

class _HomePageState extends State<HomePage> {
  int _currentIndex = 0;
  final screens = [DonePage(), CreatePage(), HistoryPage()];

  @override
  Widget build(BuildContext context) => SafeArea(
        child: Scaffold(
            body: screens[_currentIndex],
        )