[whiplashoo]

OP here!

It wasn't that hard to handle the conditional logic for the UI components. It can also be encapsulated in a separate package, something that is already available for Flutter on mobile (iOS and Android UI): https://github.com/stryder-dev/flutter_platform_widgets

I could also not strive to make it look native, but go with the default UI (Google's Material UI). As I explained in the post, I decided to take some extra steps and use the two UI packages (macos_ui and fluent_ui), to make it adapt to the platform.

Please bear in mind that I am a single developer, with ~1 year of working with Flutter and Dart, and my main background is web development. I think that teams with more members and experience can certainly do this for even larger in scope apps.