Software compatibility on the Mac is fine, unless you mean emulating Windows for gaming like the Steam Deck does so well. In that case, I've gotten Fallout 4 to work with Whisky, but that's not a huge accomplishment. I have an M2 Pro Mac mini from 2023 and Fallout 4 came out in 2015. It's not a great platform for gaming in any case. I play Blue Prince on it and that looks good. Stray, too. Those are newer games, but not particularly demanding. They look okay, but the framerate isn't good. Xbox (Series X) is a better platform for both.
I'm not discounting or disregarding the Deck, I just haven't got one so I cannot say what it can or can't do. I've only heard good things about it. I have a friend who may be trying to unload one, I just can't spare the cash right now and I'm not that interested in owning one. And I think he does have the most expensive version. And I think he's upgraded the SSD in it. So sure, it would be a good deal and he'd make a good deal for a friend, I just don't really have the room for it. Still, it is tempting.