There are distributions with a great Steam experience out of the box? It's SteamOS actually a good choice? Maybe isn't what you use or prefer.
A good Steam distro for me has a very mininal procedure for perfectly working controllers, client and general user experience.
Your direct test and experience are very appreciated.
I havent used any myself but from what im aware of,
ChimeraOS and HoloISO would be the cloest to a console like experience
Nobara and Garuda is a step away from that and focuses more on being a gaming pc rather than a full console experience.