I really want native apps to be as simple to work with for UIs but it's just not. Qt is great but still more cumbersome and I'm not aware of anything better that gets you close to the development speed and flexibility given by HTML and CSS.

Very honestly: please let me know if there is anything. I really would love to build more native apps without fighting the UI system

What do you mean, fighting the UI system? Non-native looking UI elements? If that's the case, I have to agree with you, actually. For web-like desktop GUIs, web technologies seem to be the fastest vehicles, unless someone releases an updated Display PostScript…

Other than that, I've had way faster dev experiences in Delphi, Cocoa, SmallTalk and Tk. Mostly because you don't have to reinvent the wheel.

That is exactly what I mean. There's benefits to using native UI elements but they really limit your creativity. It's also difficult if you're building something for multiple platforms but you want to make sure that you have a consistent experience.