Something like SwiftUI but open source and targeting GTK4 would be pretty close to my "dream framework" for cross-platform desktop UI.
I will admit, Swift syntax is an acquired taste, but once you're familiar with all of the concepts (and understand that some design decisions were made for Objective-C interoperability), then it's a very usable language. To be frank, the only thing that stops me from using Swift is the fact that Linux support isn't as good as on Apple platforms. But if I am targeting nothing but Apple platforms, then Swift is probably the best choice, just for SwiftUI and SPM alone.
I will admit, Swift syntax is an acquired taste, but once you're familiar with all of the concepts (and understand that some design decisions were made for Objective-C interoperability), then it's a very usable language. To be frank, the only thing that stops me from using Swift is the fact that Linux support isn't as good as on Apple platforms. But if I am targeting nothing but Apple platforms, then Swift is probably the best choice, just for SwiftUI and SPM alone.