Factorio, Warframe, Minecraft, Dota 2. However, the only two I'd still recommend are Factorio and Minecraft. Warframe's grind seems to have finally burned me out for good, Dota 2 is bad. You're not gonna have fun with Dota 2. The game concept is good, but like most competitive online games, the community fucking sucks.
In addition to Factorio and Minecraft, try Voices of the Void, The Long Drive, WEBFISHING, and Balatro.
Edit: oh yeah, and personally I have both Sims 2 and Sims 4 w/ all DLC (yeah, I toootally bought all the dlc) installed on my steam deck. Both fun games with their own ups and downs. Sims 2 is great vanilla, Sims 4 is great when heavily modded. Don't bother downloading the F2P version of Sims 4 from Origin if you're wanting to mod it with stuff like sacrificial's mods. Those'll break with every major update (and sometimes minor updates too!) and you can't pause updates anymore. So, you'll have to find alternative methods.
Maybe the community has gotten better, but back when I played it wasn't uncommon for mid to get salty because they fed early game and start feeding couriers to the enemy team.