Looking for your next RPG-shooter hybrid with online co-op? OUTRIDERS from People Can Fly recently released the WORLDSLAYER expansion and it's now actually Playable on the Steam Deck (and Linux desktop too). Previously it had problems with Easy Anti-Cheat but that is no longer an issue.
Currently you need to set it manually to Proton Experimental (guide), as a very recent update stopped it working on Proton 7 and if you have any problems, just ensure you have the "Proton EasyAntiCheat Runtime" installed in your Steam Library. I imagine very soon it will be re-verified and set properly to Proton Experimental so you won't have to do that.
The developer even tweeted a brief announcement video about the official Deck Playable status. It appears it's Playable and not Verified due to needing the on-screen keyboard to be opened manually (Steam + X).
Here's a look at it on Steam Deck:
I think I'm going to enjoy this one…