Reason is simple. React Native abstracts only platform away by exposing base components. If you really need something for a specific platform it is very easy to write a custom plugin - so you will need some platform knowledge. I have used flutter as well but must admit it feels not the way as I would like to have - especially the shader compilation if a component gets shown for the first time I feel annoying.
So to me react native is best - but comes with its own pain points like updates...
If you can afford it go pure native and try to write business logic in a shareable language e.g. Rust, C, C++, Kotlin native... and integrate the UI based on the platform.
If thats not an option I recommend react native + if needed custom modules and try to not use too many third party libs.
Hey,I just have started a series of tutorials for people who would like to use Godot in conjunction with GDNative script using the Rust programming language. I cover some basic setup and other stuff like debugging. Happy to get your feedbackYou can find the tutorial overview here: https://github.com/Schr3da/godot-rust/blob/master/README.md