I’d suggest Pop!_OS (Ubuntu-based) or Manjaro (Arch-based) as easy-to-pick-up distros with good gaming support out-of-the-box. Mint is nice for beginners as well but I have no idea if you need to tinker to get gaming working well.

I made the permanent switch from Windows four years ago. First to elementary OS but I found it severely lacking for gaming purposes and also for my power user needs. After a year of cursing and banging my head against the wall I switched to Pop!_OS for a couple of years. It was pretty great for everything I needed, including gaming. Except that I had constant problems with updating the proprietary Nvidia drivers to the point I once had to reinstall the entire OS to get my display to show up again. And also a lot of audio problems. It was a huge learning experience though!

I decided to try out Manjaro last summer and have been very happy with it since! I only booted back to Pop twice (just to check and copy some configs) before wiping its drive clean and never looking back. Pretty much everything just seems to work, especially gaming and the Nvidia drivers!

Orange Pi PC (Allwinner H3, 1GB LPDDR3, HEVC support built-in). I was skeptical that the HEVC decoding would actually work with Armbian as it does with OpenELEC but it would seem so. At least I’ve had no problems with it while I previously had severe transcoding delays for x265 videos when running Jellyfin on a RasPi 2.