Sims 4 is free, and there’s a DLC unlocker that lets you get all the DLCs in your legit copy. You might have better success installing the EA app in Proton/wine, logging in a throwaway account, and then installing the official base game.
I also recommend Lutris instead of Steam for non-Steam games, I’ve found it easier to work with and it can also automatically add links back to Steam if you like having all your game in one place.
Let’s get MasterCard on the case