Steam 'Remote Play Together' is now in Beta, allowing local multiplayer games over the net
Today, Valve have released an exciting update to the Steam Beta Client which adds in Remote Play Together, allowing you to play local co-op, local multiplayer and shared/split screen games over the net with your friends.
How to setup OpenMW for modern Morrowind on Linux / SteamOS and Steam Deck
How to install Hollow Knight: Silksong mods on Linux, SteamOS and Steam Deck