Sounds like you have the compositor off,try ALT + SHIFT + F12 to activate again.
Then check in System Settings > Display and Monitor > Compositor and make sure Enable compositor on startup is enabled.
Do you have the compositor off ? try ALT + SHIFT + F12 to activate again.
Then check in System Settings > Display and Monitor > Compositor and make sure Enable compositor on startup is enabled.
It’s maybe like this because of your set resolution. Just set the resolution to 800p.
This is technically a docked set up.
And by the way, the steam deck Resolution isn’t 16:9 it’s 16:10 I don’t know why they did that