Option 2

1_start_of_app.dart

class Vehicult extends ConsumerWidget {
  @override
  Widget build(BuildContext ctx, WidgetRef ref) => CustomFutureBuilder(
        future: DataController.fileDB.processSettingsFile(),
        loading: RowLoading(),
        onDone: (st) {
          ref.read(settingsProvider).set(st.data);
          return MaterialApp(
            title: 'MyApp',
            localizationsDelegates: AppLocalizations.localizationsDelegates,
            supportedLocales: AppLocalizations.supportedLocales,
            theme: ThemeData(primaryColor: PrimaryColor),
            locale: ref.watch(localeProvider),
            home: _getHome(ctx, st.data[6]),
          );
        },
      );

2_settingsAsyncNotifier.dart

@riverpod
class SettingsNotifier extends Notifier<Settings?> {
  @override
  Settings? build() => null;

  void set(Settings settings) => state = settings;
}

final settingsProvider = NotifierProvider<SettingsNotifier, Settings?>(
  () => SettingsNotifier()
);

3_inkwell_saving_settings.dart

InkWell(
    child: Icon(Icons.check, size: 32, color: Colors.white70),
    onTap: () async {
       await DataController.fileDB.writeSettingsFile(settings); // it's a void 
       ref.read(settingsProvider).set(settings).
    }
),