Xamarin makes this separation work pretty well. Not Xamarin.Forms but a core business logic project with custom UI projects for each platform.
I'm hoping this will turn into a good solution. Xamarin already supports Mac (in addition to iOS and Android) and when it aligns more with UWP (XAML Standard etc.) that could cover a large slice of the platforms you'd want to target.
I'm hoping this will turn into a good solution. Xamarin already supports Mac (in addition to iOS and Android) and when it aligns more with UWP (XAML Standard etc.) that could cover a large slice of the platforms you'd want to target.
React native could be another option. I hear Android support has gotten better and you can supposedly also target UWP: https://github.com/Microsoft/react-native-windows
I wrote this a while ago but it's still fairly relevant: https://unop.uk/cross-platform-native-mobile-app-development...
You could also look at https://github.com/AvaloniaUI/Avalonia or https://github.com/picoe/Eto.