Summary of cross platform framework:
- Qt - UI is too old and outdated; complicated build process for mobile
- React Native - Not pixel-perfect as it just maps to native UI;
- Kotlin Native - Ecosystem is very poor but the good thing is you can use the native libraries in each platform and create wrappers to unify them; also the framework itself hasn't yet reached production stage; you have to write the UI separately for each platform
- Flutter - Very poor ecosystem/libraries;
- Xamarin Forms - Like react native as it maps to native UI; slow startup;
- Xamarin Native - Like kotlin native as you have to write separate UI codes for each platform; but uses arguably the best programming language in C#; and backed by Microsoft which is even more reliable than Google; also supports the most number of platforms including UWP, WPF, MacOS, etc. on top of iOS and Android; you have the support of the entire .NET ecosystem
- Nativescript - Performance is terrible (build time, startup time, Angular performance, etc.)
Reference:
https://amp.reddit.com/r/Kotlin/comments/bo1ur4/kotlin_vs_qt_for_mobile_apps/