It is all in the context. But note that was not my comment. That poster was suggesting to rsync the
/home/user-data/ directory as an alternative to restoring the backup. I agree that is an easier method to proceed - IF you have a good knowledge of what you are doing and using rsync.
Digital Ocean is the default provider suggested by this project originally, so my answers tend to fall within the parameters of using Digital Ocean.
Digital Ocean offers the ability to create snapshots and to restore those snapshots to a different VM within the same data center. So this advice is applicable if moving within the DO infrastructure.
Spin up a new droplet installing Ubuntu 22.04
rsync your data backup from the original droplet to some directory out of the way on the new droplet. (Alternatively, as the comment you’re referring to was suggesting, use rsync to move your data - note this is for experienced users only!)
Restore your backup.
Once confirmed that all is good, make a snapshot of the new droplet.
Then reinstall your old droplet with the snapshot from the new droplet.
sudo mailinabox from the command line to insure that all settings are correct.
Now you have migrated to Ubuntu 22 while retaining your original IP address.