I don’t buy your claims on hot reload. For the record, see the video here to make sure we are talking about the same thing: https://flutter.dev/docs/development/tools/hot-reload.
It is actually takes more than the language to have meaningful hot reload. With flutter it is also the whole way that state is handled that helps hot reload to work.
Android itself has had an instant run feature for a long time that claims to be like hot reload, but in my experience was completely unreliable and rarely ever actually worked. So much so that I always just disabled it. Here is a comparison of the 2: https://stackoverflow.com/questions/52050660/difference-between-androids-instant-run-vs-flutters-hot-reload-and-react-nativ
And Hot Restart is definitely not comparable. Imagine working on a screen that requires logging into the app and navigating through several steps to get to that screen. Having to do that every time is a big pain in the butt and part of why hot reload is so game changing.
It would actually also be possible to take the Flutter UI widgets and stack and port it to Kotlin to use for the UI. That way you could actually only code the UI once. You would not have the benefit of all the community flutter libraries, but is possible.