It appears that Apex Legends from Respawn and EA has started banning some players on Linux, and while the Steam Deck uses Linux too it seems nearly all the bans were desktop Linux players.
Currently in Early Access with Native Linux support and rated Steam Deck Playable, the inventory management roguelike Backpack Hero is releasing in full in May.
Totally Accurate Battlegrounds got upgraded recently due to needing to implement new anti-cheat, and thanks to that this free to play game now works on Linux Desktop and Steam Deck.