I have whitelabeling for my apps for different customers that are all based on the same app. Only minor configuration changes needed on the app.
One thing I find hard to figure out is a nice way to configure for different Bundle Id and Package Name. (Current solution found is refactoring which changes whole lot of code). The main purpose bundle ID change is to upload into different appstore, push notification all requires specific bundle ID.
In IOS, its quite simple, you change it in Bundle Identifier. In Flutter, its also simple, just Bundle Identifier change.
I feel there is a proper way to have Bundle Identifier configuration/variant management for Android without doing a whole refactoring.