Steam Overlay not showing up but Steam Client shows game as running (Linux)

I’m trying to setup Steam for my Game following the [Online Subsystem Steam Interface in Unreal Engine | Unreal Engine 5.5 Documentation | Epic Developer Community](Online Subsystem Steam) Docs.

After following all the steps and trying to launch the game in Standalone or a build version, I can see in the Client that i’m playing Spacewar (480) like i set in the “steam_appid.txt” but the Steam overlay won’t open.

I’m a bit clueless what could be the error here and hope maybe you have some ideas.