Same here, at some point I just did a reinstall of Batocera. After that the first few flatpaks seem to work for some time. After a reboot they all had the kickback to the mainmenu issue. Tried months to get Steam working ‘permanently’ but gave up eventually. I ended up with a dual boot Batocera/Windows 11 with steam on Windows…
I gave up for now and will try again when Batocera 37 stable is released.
By the way, too bad, but understandable that the forum is closed for now. @Atari, Thanks for the support you gave me from time to time :)