Here's a fun one I managed to somehow miss recently, but it seems that Hell Let Loose has hooked up Easy Anti-Cheat to work on Linux / Steam Deck.
Not a big surprise though, considering they clearly stated it was in their roadmap, but it appears the addition came without any proper announcement I can find. Seems it was added around a 1-2 months ago. You just need to ensure you have the "Proton EasyAntiCheat Runtime" installed in your Steam Library, and then it should work with Proton 8.
More about it:
Take to the battlefield in this squad-based, 50v50 multiplayer game, and choose one of our 14 roles available within the Command, Infantry, Recon and Armour unit types. Play as an Officer, Spotter, Medic, Tank Commander and more, to experience every aspect of World War II combat. Each role is equipped with different historical weapons, vehicles, and equipment that are intricately detailed, bringing the realism to the brutal and bloody warfare. Unit focussed gameplay is crucial and when done well can command the tide of battle.
There's plenty of reports of it working well on ProtonDB.