I am entirely unsure what is the problem entirely, what DE are you using ? I am currently on KDE and it works there but I honest to god can’t see any issues on the log itself. You can try adding using the --expose-waylandcommand and seeing if that works, or try using gamescope-plus on the AUR, built by the Chimera devs. If all else fails, I would send a bug report to the gamescope github.