> I think SwiftUI is the winner if we're going to put names forward. But arguably, not cross platform.

I must have a very different understanding of the word "arguably" than you. To me, it's arguable whether Swift itself is a viable cross-platform language today. SwiftUI, on the other hand, supports literally zero devices not manufactured by Apple.

Is it really arguable that when people say "cross plaform" when referring to a GUI framework, they aren't counting "both macOS and iOS, but not any of Windows, Android, Linux, web"? It might be accurate from an pedantic standpoint, but I have trouble imagining a context where someone would bother using that phrase as a qualifier if they understood it that broadly.