I have been using Batoreca Linux for a few years now, and it's been great. Until the last 6 months I hadn't used Batocera for Steam or Epic games that much, but figured I'd give it a try so I could play Deep Rock Galactic: Survivor.
It was great, I turned down the specs on my game to make performance on my Acemagician ARM5, and it played beautifully and was quick to start - I'd found a new love for Batocera...then came v39.
Steam support is broken in v39 onwards and I'm not sure there are any major plans to address it right now, infact the Flatpak integration that is used to install Steam/Epic etc. is under consideration to be removed. I believe the issue overall is a lack of developers to support the integration and keep it stable. There are some workarounds using Batocera Pro installation files that basically install an Arch Linux container, but it seems like overkill.
Time for a change
At this point I decided to search for an alternative to Batocera, I wanted an OS...not just an application sitting on top of an OS i.e. Lutris or RetroBat.
My research found limited options (SteamOS - discontinued I believe, HoloISO - end-of-life), and in the end I was left with ChimeraOS. ChimeraOS, as far as I can tell, is a Steam Deck OS for PC.
How it fairs
ChimeraOS has been great, I can play several of my Steam games with ease, and there are retro and alternate game library providers, such as G.O.G and Epic store.
Installation of games outside of Steam is done via a web interface, navigate to your ChimeraOS IP address and add the port 8844 for the webui.
Conclusion
For the time being I've moved to ChimeraOS, as I want to continue to play some of my Steam games. Retro games, so far, appear to require installation individually...I guess I could install RetroArch on Steam and try importing, but haven't played about much.
What will I miss from Batocera: RetroAchievement integration and Syncthing support. Both these features add a little extra to Batocera, getting RetroAchievements on my old games and syncing games/saves/bios with ease between multiple devices.
What do I like about ChimeraOS: Ease of installation, simple third-party game library support. Flathub potential - the ability to install 3rd party applications into Steam e.g., Firefox, Discord, WhatsApp...and dozens more)
What to be aware of - ChimeraOS like all other Steam Deck OS implementations required an AMD GPU, Intel or NVIDIA are not supported.