Qt look out of place no matter what OS you use them on though. So I don't feel that is a fault of Elementary OS.
I've been running KDE Neon and they don't look out of place.
KDE does a better job of naturalizing GTK apps than the other way around.
I just use the Arc GTK theme and use the kvantum Qt theme’s Arc preset. Makes both look pretty much the same. Qogir is another one that’s kind of cross-desktop.