Filling in the gap left by Valve leaving SteamOS alone, the sofa / couch gaming distribution GamerOS has a brand new release available with the usual great improvements.
Booting directly into Steam Big Picture mode, the idea is to have this as the only install on a machine hooked up to a TV. Perhaps in a living room or a dedicated gaming room. It takes things a step or two further though, including plenty of extra enhancements for emulators and non-Steam games with their special tools like Steam Buddy.
GamerOS 23 went out on March 6 with the usual back-end upgrades to the main components including Linux Kernel 5.11.1, Mesa graphics drivers 20.3.4, NVIDIA graphics driver 460.56 and updates to the compositor, their Steam Tweak and Steam Buddy tooling. For emulators they now support save states, Steam Buddy had some styling changes and fixes to the virtual keyboard, Proton 6.1 GE-2 was added plus Moonlight, Chiaki, and Chromium are available as Flatpaks now too.
The developer has also "certified" more games to work with GamerOS, which means they've been setup and tested working properly. Games tested include Linux supported games, and also Windows games run through Steam Play Proton. Newly certified games include Lovecraft's Untold Stories, Moving Out, Valkyria Chronicles 4, Valfaris, Control, Hotshot Racing and more.
More info on the GamerOS website.