Linux

Probably not. SteamOS likely won't have any particular benefit on desktops over other distros.

Just download an Arch-based distro, like CachyOS or EndeavorOS, install the Steam app through pacman -S or whatever helper app they have for new users, install Proton Plus, and play your games. If you want to get into the weeds of immutable Arch, give blendOS a try.

I recommend, trying all of these in a VM first, btw. You can even practice doing a pure Arch install from scratch that way.

Anyway, SteamOS is almost certainly just a preconfigured Arch + KDE that has Steam and Proton already installed, with downstream patches for specific hardware they've deemed worth their time to patch (which will eventually make their way upstream).

Knowledge can't hurt, but probably not. Valve seems to be aiming at a OEM experience out of the box, and we don't know what the installer for desktop would look like. But it would certainly be some kind of install wizard. Arch based distros use stuff like Calamares.

You can't install steamos, as it's not availble as an iso with an installer. Holo iso is an unoffiial installer for steamos

Installing arch nowadays is not complex at all, there is the command archinstall, so it's just a meme now. If you are somewhat familiar with computers and linux, and don't call someone a "haxor" just for using a terminal, it won't be a big deal.