Well, yeah. Windows is... special. Even Microsoft stopped using the normal controls. But the problem is that Qt looks like an uncanny valley version of those Windows 95-style apps.
But by Premium I'm talking more about macOS, iOS and Android.
For macOS check apps made by Apple, Panic, Rogue Amoeba, or apps like Pixelmator, Affinity, Pixelmator, TablePlus, FantastiCal, Tower, Dash. Or even "non flashy" apps like Pacifist.
Those all use Cocoa and have a bit more of a slick appearance, even though they're mostly using native controls, with very few special parts here and there.