I just use vanilla debian and Steam works great. Just set it to launch steam on login and set your system to auto-login, that should get you most of the way.

You can use the Steam Deck recovery image to flash an SSD with SteamOS. It's what those of us on other handhelds do.

Have you tried Bazzite? It’s basically a drop-in replacement. It’s based on Fedora’s Atomic stuff instead of Arch, but if it wasn’t for the logo at the start, I’d be hard pressed to notice I was using it and not vanilla SteamOS.

I did try using Bazzite but I had weird issues with stuttering/throttling on the RX 7600 which made most games totally unplayable (I confirmed the same hardware worked fine on a windows install). That was a while ago though, it's probably worth me trying again.

Normally I just use regular Fedora/Arch/OpenSUSE for gaming on Linux and never see any issues (albeit that's on a 6800xt at the moment) but I want that consolized experience.

edit: found the thread where I discussed fixing this - few bits of false hope and then I eventually gave up. https://www.answeroverflow.com/m/1314736793190662216

Have you tried CachyOS? May get the results you are looking for with Desktop or even Handheld addition.