I did both, and they both went without a hitch.
The only reason I backed up and reinstalled was because I wanted to move to ZFS.
I have one issue though. For some reason, even after a full new install and restore, I'm still not getting the option to update to 22.01. I already registered and have the activation key in my email.
I even tried "pkg-static clean -ay; pkg-static install -fy pkg pfSense-repo pfSense-upgrade", and rebooted, just in case Tried to halt, unplug for 1 minute (I know it says 30 seconds, but I don't believe in "overkill"), booted back up, all to no avail.
I do use an actual Qotom device for my PFsense, so your mileage may vary.