Unfortunately display safe mode is the main way I know to fix issues like this. Someone mentioned deleting .local/share/kscreen and rebooting as a way to reset screen settings, but I would assume that only fixes desktop mode.

I’m not sure how settings for game mode are saved though. Gamescope is what provides the VRR functionality, so there would have to be a configuration file somewhere that it references for different games/displays. There’s a chance it’s using the same kscreen file for some of the settings, but I doubt it.