> If I were to build an editor, I’d want the GUI platform-native so would probably go straight for Xcode and Swift.

That's where we'd diverge. I'm a heavy user of Flutter especially in the age of AI because even if you could have the AI rewrite 6 different version for 6 different platforms, it's just a waste of your own tokens. Rust for desktop is good enough these days, with GPUI or iced, etc.