I have tested a lot of atomic and traditional distributions lately. Tons of desktop environments strictly for fun and branching out. Having a 1 2 3 backup strategy and not just having it in place, but being able to restore your backup in a timely manner to keep continuity is paramount. You can list infinite reasons why.
Why do atomic distros which are supposed to me more stable, superior to some degree immutable environments lack good backup options? You can hack things together and there are somewhat installable tools. Like timeshift or etc etc. But it seems they place a lot more emphasis on rolling back poor updates in the event than total system backups.
By default it you should have true backups then layer in rollbacks. Not the other way around. Am I missing something?
I think you misunderstand the point of atomic still. Your base system should be installed entirely through ublue or other. Every time you update ublue will hash it and you can go back to that exact config with a working base system. Flatpaks and distrobox are user applications and should store all the data they need somewhere under your /home. Back up your /home and /etc with rsync or similar. When all is said and done your be able to recreate your system with ublue, and restore your configs and personal files with rsync.
The advantages of ublue is you can easily share or restore your base system without needing to backup gigabytes of data every update