I am coming from KDE, and I am used to theme the applications there with the System Settings app. Obviously, I dont get to do that here, but I installed KDialog, since it is compatible with Firedragon, and because I like to.
I managed to get it to an usable state.
I have to say, something is not right with the communication between Qt5-Settings, Kvantum and KDialog.
Kvantum itself is themed by Kvantum as well, and I see the changes always and immediately.
Half the time, it seems like KDialog is not being reached, or doesnt react properly to the changes, and sometimes it takes like 3, 4 seconds. A bit weird, but ok