I’m using EndeavourOS with KDE.
The display is correctly oriented when logged in but it doesn’t rotate correctly when I’m logged out.
EDIT: corrected the post. This happens when logged out, locking the screen has it displayed correctly.
You can’t be this stupid, Wayland also uses a config file, you just have a GUI button to copy the configs from inside your session to the login screen. Or do you think the button recompiles the login screen with a different configuration?
Ironically SDDM itself still runs on X11 afaik, Wayland support is still experimental.