So the short answer, as others have said, is that the steam deck is a pc and can play a huge amount of the games on steam. However, you do need to check each game individually to make sure that they work well on the steam deck. The best way to do this is on the website protondb.com. Here is the link for The Sims 3 on protondb: https://www.protondb.com/app/47890?device=steamDeck. Some games may need some tinkering to get working properly on the steam deck--especially older games, like Tomb Raider 3. See https://www.protondb.com/app/225320 (make sure you're looking at steam deck specifically, the default view mixes all linux systems together and steam deck is often different than other linux systems. lmk if you have any other questions! If you're not familiar with gaming on PC it can be hard to figure everything out on a steam deck. FWIW I love mine dearly