No.61931
That's the old version of Steam OS. The one you find on Steam decks is based on Arch, I believe. It doesn't really matter what distro you choose to game on though, because the experience is mostly going to be the same unless you're on a distro that only allows you to install free and open source software or has some other purpose. For a complete beginner, I'd recommend Mint or Debian, personally I use Debian. Just stay away from Ubuntu, Steam on Ubuntu and any of it's flavours (Xubuntu, Ubuntu MATE, Kubuntu, etc) is absolute cancer.
Another thing to keep in mind, and I can't stress this enough, is that ==LINUX ISN'T WINDOWS==. You will have to eventually learn how to do things differently, and that means using the command line. There's GUI tools for most things now, but the CLI is the best thing about Linux. If you use Linux like people use Windows, it will eventually break.
No.61932
Try the non-GUI version of Steam
No.61939
>>61929>SteamOS Ubuntu is the first option, specially if you have old hardware. Both Debian Pop OS and Mint have given me trouble recently with old hardware (Basic shit like an old IDE hard drive, probably due to no compatible drivers found for the motherboard's chip set).
Both Pop OS and Mint have good reviews specifically for gaming, that is why I was trying to install those. If you have new hardware you can try them out.
I have never tried SteamOS.