I can’t speak about Flutter or React Native, but what I can say is DON’T use Xamarin Forms/MAUI. As a native Android developer I had to start using Xamarin after changing jobs and it’s been one of the biggest regrets of my career, honestly. Literally nothing works like you would expect it to. I understand the idea of writing the same code twice is intimidating, but trust me, nothing beats native development. Nothing. I can say with 99.9% certainty, you will regret not going with native if (or when) your app requires any vaguely complex feature to be implemented into it. Swift and Kotlin are similar enough that you can literally write the same app natively for both platforms faster than it would take you to write them in any cross platform framework (or at least Xamarin/MAUI), unless you’re making an extremely simple app with no customizations whatsoever.

I’m a react native and flutter dev. They’re very, very good for 90% of use cases. Even if you’re only developing for one platform, they’re actually quicker to get started on and be productive than native development, especially if you use something like Expo to get your app started as fast as possible. If you’re doing performance critical applications or need access to hardware other than the usual camera/Bluetooth/internet, then you probably are better off writing it natively but that describes a very small handful of real-world apps and you can always selectively write some parts in native code.

EDIT: Also I didn’t think it had to be said cause I thought Xamarin was basically dead but yeah, Xamarin sucks major ass.