You can "hack" the flutter_local_notifications MethodChannel the plugin uses to invoke native functions and do something like this:
const MethodChannel localNotificationsMethodChannel =
MethodChannel('dexterous.com/flutter/local_notifications');
Future<void> deleteNotificationChannel(String channelId) async {
await _localNotificationsMethodChannel.invokeMethod(
'deleteNotificationChannel',
channelId,
);
}
I used this because I needed to customize the notification sound (based on user settings for the app) and the only way to do that was to create a new notification channel when the notification sound changes, and I didn't want my app notification settings to be flooded with unnecessary channels.