When a platform can’t answer “how should I build a UI?” in under ten seconds, it has failed its developers. Full stop.
That's fine, except no platform answers this.
Obviously Linux doesn't, but the Mac doesn't either. Apple of course has it's recommendation, but most developers do not take Apple's recommended path because of course, it's Apple-only, most developers make cross-platform apps these days.
Even if Microsoft decreed the one-and-one Windows development path, most developers are not taking that path.
It used to be the case that Mac developers used Apple tools, Windows developers used Microsoft tools, but those days are gone. Developers want to use Electron, or Qt, or some other system to support multiple platforms in one codebase.
Microsoft has less to do with this than the article makes out. I'm a desktop developer. I don't care what Microsoft recommends, or what Apple recommends, because neither work in the real world where supporting only their platform just isn't realistic.
I think the mac mostly does this. Developers not caring about the answer is a different thing.
But I gather from your comment that you don't actually care to ask that question, since you have a different need, and already have a solution which works for you. Which I guess is fine if you're happy with the compromise.
But this is about people who actually still care to have "native" applications.
Linux can answer the question, but you're considering Linux as a monolithic platform which it isn't. If you ask "how do you build a UI for Gnome / KDE / Android?" then the answers are pretty clear.
Also, being KDE native means using QT which is a good cross platform toolkit anyways.
Tbh Qt is so big you've still got a few minutes of decision making after you've decided to use it. What parts will you use and how will you use them?
...but then feeling out of place on GNOME / GTK4 / LibAdwaita-land
Linux is a mess, but at least it's unapologetically so.
They've got unified themes that make GTK and Qt applications look nice alongside each other. Users who care will be using those. Users who really care might refuse to use your application because it isn't the toolkit they like, but you shouldn't lose sleep over satisfying such particular and demanding users. They're not paying you anyway.