Flutter Timer widget still playing after navigating to another screen

in my app I have custom splash screen, I made it the home page in the MaterialApp and there is a Timer inside the build method of the screen main widget and after 3 seconds the Timer callback function navigates the home widget

Timer(Duration(seconds: 3), () {
  Navigator.push(
    context,
    MaterialPageRoute(
      builder: (context) => HomeScreen(),
    ),
  );
});

The problem is that when I am working on the app and perform any hot reload, the hot reload runs successfully and the changes appears, but after three seconds it redirects me to the HomeScreen(), it feels like the Timer widget is running after any hot reload even when I am not working on the splash screen anymore

I need a solution, I thing the will affect the performance of the app
how to stop the splash screen logic after the Timer finishes the first time?

Note: I am using BLoC cubit and the BlocConsuming on the screen and there is no dispose() functions - I can't use them

I tried to call the Navigator.pushAndRemoveUntil() but it shows me this error Unhandled Exception: Null check operator used on a null value

Timer(Duration(seconds: 3), () {
  Navigator.pushAndRemoveUntil(
    context,
    MaterialPageRoute(
      builder: (context) => widget,
    ),
    (Route<dynamic> route) => false,
  );
});

you can declare the timer

Timer? timer;

use like this,

timer = Timer(Duration(seconds: 3), () {
        Navigator.push(context,
          MaterialPageRoute(
           builder: (context) => HomeScreen(),
            ),
          );
       });

you can cancel the timer in the ontap or dispose method like this.

timer.cancel();