I think that if you’re looking for a Linux distribution that is as polished as the Steam Deck, then SteamOS on desktop might not be the right play. SteamOS will probably (rightfully) be developed solely for handheld, low-power devices, and won’t work unless you’re using the specific APUs that they’ll include drivers for.
If that sort of streamlined experience interests you, Bazzite has very similar goals to SteamOS (good OOTB gaming experience, safe updates etc.), except that they also target wide hardware compatibility. Other gaming distros exist, but I’m probably just not aware of them.
You may want to check out this thread from GrapheneOS: https://grapheneos.social/@GrapheneOS/114235396540176085 They are technically competing, but their points about lack of support and slow update speeds are still valid.