The arch wiki is the gold standard for Linux, not just arch. But it definitely talks specifically about arch.
So, there are built in install scripts now. There's no GUI installer, but it's 1 command to get a full arch setup installed with a desktop environment. Arch is a 100% reasonable choice for a new user.
Steam is not in the AUR. Arch's main repos have way more than Ubuntu and Debian. And then the aur is a better alternative to installing from source or doing other hacks