Basically a good distro + Steam is similar to Windows + Steam, with all the proton stuff and the same (optional) big picture mode as the Steam Deck. It'll handle setting up most games for you real nicely.
For a DE personally I love Plasma; xfce or Cinnamon would be my next choices. I don't understand why so many power users like the modern gnome (Ubuntu default)
Random other tangent: I really miss the old Big Picture mode. Few things about the new one are good, but most is worse and a few things are relatively broken still. I know I'm in the minority thinking that though