@alkonaut 12d
I guess you can't have it both ways. I think (and this is perhaps controversial even though it shouldn't be) apps looking "consistent" on desktop is a ship that sailed long ago.

I use a handful of apps on desktop and they don't look consistent anywhere. Spotify, VSCode, Rider, etc. Desktop design has entered the same space as web design now. Not just for the Spotify-ish apps that are basically web like, but also for everything else. The Win32/Qt/etc era is gone. Dead. It's not coming back.

The OS should provide services though for security and UX consistency in a few cases. One example could be permission dialogs, file dialogs and so on. That does mean that it's a jarring UI jump to go from the app to a dialog opened by the app, but that's fine and unavoidable.

But in the end it comes down to this: do I want my app to look the same to everyone, or do I want my app to look the same to the user as the other apps on the user's desktop? And my answer 20 years ago was "desktop consistency!" while my answer to day is the opposite. Consistency within the app is important for usability though (here is where Windows itself fails with its hodgepodge, since you can argue it's a single "app"). But consistency between N apps running on the same desktop? Not happening. Given that, I'd consider it quite a nice feature to be able to "freeze" my app, and not risk a future update of it sucking in newer OS libraries. The trend is towards more and more self contained apps with vendered everything.