Generally the distro should handle that if you're not using something that requires manual intervention. If you are, Kvantum is pretty solid, it provides themes based on Adwaita or Libadwaita, as well as many other themes which KDE uses.
You'll have to set the theme to Kvantum which I think qt5ct and its Qt6 ilk should handle.
I guess people don't realise Qt exists.
And it's so easy to use as a developer! I hate having to think about both GTK and QT themes though. I wish there was a QT equivalent of lxappearance.
That would be qt5ct/qt6ct
Generally the distro should handle that if you're not using something that requires manual intervention. If you are, Kvantum is pretty solid, it provides themes based on Adwaita or Libadwaita, as well as many other themes which KDE uses.
You'll have to set the theme to Kvantum which I think qt5ct and its Qt6 ilk should handle.
I use a tiling window manager on a fairly minimal install of Debian.
Then yeah, qt5ct + qt6ct will help you there. Kvantum will help if you've got a specific theme you want to use.