The Mass Effect™ Legendary Edition includes single-player base content and over 40 DLC from the highly acclaimed Mass Effect, Mass Effect 2, and Mass Effect 3 games, including promo weapons, armors, and packs — remastered and optimized for 4K Ultra HD.
Yeah unfortunately it has the awful EA launcher tacked onto it, which you also need an account for. I had to launch the game from desktop mode to actually get through the EA login for the first time. After that steam does a pretty good job of keeping it out of your face. Every once in a while EA updates it and breaks a bunch of things, then Valve fixes it again. Fucking EA.
Edit: The games work great otherwise. I always check here before buying: https://www.protondb.com/app/1328670
There are tons of games that Valve has not verified but still work great on the deck.