
-pipewire flag to steam in gamemode/usr/share/gamescope-session-plus/sessions.d/steam would work but is readonly-pipewire in here https://github.com/ChimeraOS/gamescope-session-steam/blob/015e09825d4f9a2dfdbc20fc2711e2dcee2af68a/usr/share/gamescope-session-plus/sessions.d/steam#L98C1-L99C1 or a patch-pipewire with kde plasma be like
/usr/share/gamescope-session-plus/sessions.d/steam