How to make Flutter app font size independent from device settings?

 Widget build(BuildContext context) {

  return MaterialApp(
    title: '',
    theme: ThemeData(
      colorScheme: ColorScheme.fromSeed(seedColor: Colors.black),
      scaffoldBackgroundColor: Color(globalBackgroundColor),
      useMaterial3: true,
    ),
    home: const MyHomePage(title: ''),
    builder: (context, child) {
      return MediaQuery(
        data: MediaQuery.of(context).copyWith(textScaler: const TextScaler.linear(1.0)),
        child: child!,
      );
    },