So, was having issues before, my own fault for trying to partition the system drive I guess. No big deal, figured I'd do a fresh install...
So far, the issues have been growing, but I've worked out all except:
No user group was created, and any time I try using the web-gui to create said group, it just doesn't do anything. (able to type it in, click save, nothing happens)
Plexmedia server didn't create a plex user. I tried to command line it, with a script found on the plex site. Entering it a second time returned that it did create the user, but the web-gui isn't showing it. (Actually how I found out the user group was missing was searching for the plex user... an oversight after a working install for months, I guess)
So, no idea what commands to enter to even try to create the default omv user group (45 minutes on google and my "meh I kinda know linux enough" showed no help), and I assume that the plex user issue is related to the user group not being there. Permission error? Faulty install? Issues with the old data drive somehow?