As I continue to use the Steam Deck that Valve sent over for both work and play, I tried Grand Theft Auto V and the initial setup was a massive nuisance.
Proton compatibility with Windows games is going to be an ongoing improvement for many years, and Proton Experimental is where all the latest comes in first for Linux and Steam Deck.
Netherguild is a turn-based tactical roguelite dungeon-crawler, where you command expeditions below the earth in a desperate attempt to cure a strange plague. A proper demo is now available on Steam.
Blender, the all-in-one tool for 3D creation including modelling, rigging, animation, simulation, rendering, compositing and motion tracking, video editing and more has a big upgrade out with version 3.1.
Stadia is something we don't really talk about here too much now, as Google has let it slide considerably from the original aim but it's still going and it seems Google still has some interesting plans for it.
If you want to play the classic Heroes of Might and Magic II on Steam Deck and Linux with a more up to date game engine, that includes plenty of enhancements you should look to fheroes2.
John Carmack's generosity in releasing his older source code resulted in a proliferation of free first person shooters in the 2000s, but Dutch programmer Wouter van Oortmerssen rejected this path to forge Cube based in the same "just for fun" spirit with which Linus Torvalds first began work on the Linux kernel.
If you need another MMO fix in your life, Albion Online is pretty good and has a lot of players. It's available as a direct standalone download and on Steam. Looks like it might end up quite good on the Steam Deck.
One Deck Dungeon developer Handelabra Games Inc. announced recently that a new upgrade is available, which should make the experience on Steam Deck much nicer.