Well I've joined the "accidentally trashing your system with rm -rf" club! Luckily I didn't delete my home directory with all the things I care about, but I did delete /boot and /usr, and maybe /var (long story, boils down to me trying to delete non-system directories named those but reflexively adding the slash in front when I should not have). I have backups of those as well, so what are my prospects of recovering from this by just copying them back in using a live USB? Only issue is they're stored in my server as belonging to the server user (I assume everything in those directories should belong to root and I can just use chown?) But I also don't know if they retain the same permissions when backed up.

Has anyone had any luck recovering a system in this way? I'm hoping not to have to reinstall everything because I had gotten pretty cozy with the current installation.

UPDATE: I finally had the time to sit down and try it, and, I was at least hoping to document some glitchy or unstable behaviour but it just didn't work at all. No matter what I tried I couldn't even get the UEFI to recognize the old system as bootable, so I cut my losses and just reinstalled. Gonna make sure I have btrfs snapshotting enabled this time, which I'm realizing I probably should have done in the first place.