Gaming on the Mac is a strange beast. Take a look at some top tier games and you’ll find an array of information telling you what isn’t compatible, rather than what will work. I’m looking at you X-Com 2. Running a system a couple of years old will stand you in good stead especially since Apple hasn’t updated some product lines in over 300 days, but even then if you don’t have the top of the line model you may be struggling with some of the most demanding games.
But what if your kit is like mine, perfectly adequate for day to day use it still runs the latest Mac OS betas fine but getting your game on isn’t going to happen and funds don’t permit purchasing of a new shiny? There’s retro gaming.