Regardless of which compatibility layer (Proton 4, 5, 7, 8, 9, 10, experimental) I use and if I use the native libraries or Steam’s, the discovery services work, but I can’t see other players in the Anomaly.
Weirdly enough, on Steam Deck it works without any issues, but obviously I want to play this on my beefy gaming PC 😥
How can I fix this?


Regular Arch. My Steam Deck has the same network and works fine.
Self rolled arch, do you have ufw installed?
Since your steam deck works fine you can look for traffic with multicast or steam services