Sorry, maybe I’m a bit out of the loop, but what is “mrrp”? I tried to google it, but couldn’t find a Linux related thing.
About reliability, I think having something like the rollback in Fedora Silverblue (or even just Snapper from Suse) is superior to a “stable base”. With something stable, you basically say “Hm, we don’t need a backup, it shouldn’t break anyway”, but when it does, which it can and maybe will, you’re fucked.
I already broke my Silverblue install a few times, but getting a working system again was just one reboot away, no restoring or troubleshooting required.