SteamOS has been out on Steam Deck for 18 months, but still no general release in sight. I wouldn’t hold my breath. I think we’ll just have to continue to make do with the likes of ChimeraOS/Nobara.
I had no idea they switched distros. Or ran Wayland for that matter! Truly it's the future. But that's a good point, being able to say on the "box" that is specifically runs SteamOS certainly brings about a level of consumer and investor assurance.
As far as the nvidia drivers go. Only advice I can offer is that I've never had any sort of auto install, package based install, or any sidestepping of the default installation of the driver work for me. It's always borked. The only reliable method I've found is the old school drop into the line terminal, shutdown all GUI, and running the nvidia provided install script (which sucks, I know).