This is brilliant work and I love the Qt ecosystem. Can’t help but imagine the things we could’ve had if Apple wasn’t pushing the horror of Swift down everyone’s throat by blocking alternatives in so many tiny ways.
Swift and SwiftUI on macOS are the most complete UI framework that is native, fast, performant and works very well.
Basically no other platform comes even close in terms of ease of use and performance. The best would be to extend that kind of framework on Windows (and/or Linux) and make it work same / similar.
If you mean due to lack of C++ for doing GUIs, Google and Microsoft have also long left C++ to the dust, in what concerns GUI frameworks.
Even Microsoft, for all its C++ use, has never produced anything better than MFC to this day, and only Windows team cares about XAML C++, others rather use React Native or Webview2 alongside C++.
It is up to third parties to use frameworks like Qt.