When you absolutely, positively must play a video file and you're not sure Apple's QuickTime player will support it, VLC is the first media player you should download. Plus, you can connect a compatible Bluetooth controller for some old-fashioned gamepad gaming on your new Mac. There are lots of amazing options too, including everything from Sid Meier's Civilization VI and Stardew Valley to Cuphead, Hades, Disco Elysium and more. Not every game on Steam is compatible with macOS, but Steam makes it easy to filter through its 50,000+ games to see which ones run on Macs.
Launched by Valve nearly two decades ago, Steam has grown to become one of the biggest PC game platforms in the world. If you want to play games on your Mac, it's a good idea to download Steam.