It shouldn't even be as hard as it appears. If the business logic is designed as a generic library made to be portable to different platforms then you can call

It shouldn't even be as hard as it appears. If the business logic is designed as a generic library made to be portable to different platforms then you can call into it from a native application built using whatever the native UI toolkits and conventions for that platform are. Libtorrent is a shining example of this architecture. It runs everywhere, even on mobile platforms. Rust being more popular with makes this even more accessible than it used to be. There's even libraries like PyO3 to make writing bindings to other languages easier.