When I first started watching videos on YouTube about people running media servers off of FreeNAS, I got excited. Actually, overwhelmed with joy might be better. My media collection is extensive.
I acquired the parts, spent more than I needed - something I learned after. What I ended up with is a server that should last me for an extremely long time.. or the rest of my life. To a degree. What did I learn? Never underestimate how much data you may have, when you've bought varying sizes of drives over the years and they're gradually getting bigger. My four by 4TB drive array was not enough to last me a few years. 10TB drives are needed, but if prices drop I may go bigger.
I got NextCloud sorta simply compared to the unnecessary struggle I went through with Emby or Plex. I think I watched damn near every recent video on YouTube on the subject. There was one video about it based on FreeNAS 10 (Corral, it looked great but had an extremely bad flaw and got trashed), and that one looked the simplest. Whether it was or not will not be known. The rage that ran through me as time after time I'd go and try and repeat what appeared to be so simple, was making me wanna sell the server I built and find other ways to store my data.
Heck, setting up Pi-Hole in a Ubuntu Server based virtual machine was probably the easiest out of everything.
About 03h00 I had an idea. It was never spoken of in the videos I've watched - some repeatedly, looking for missed clues. It always appeared, to me at least, that the directories were supposed to be in what's called a 'dataset' and shared to put media in. This is not true.
When mapping mount points for plug-ins, you need to link it to the 'share'. The share being whatever name you made that you access your personally stored files on, not some dataset owned by the system (FreeNAS). See below:
/mnt/databank01/Scrat/Media to /mnt/iocage/jails/emby/root/media
Change 'emby' to 'plex' if you're using that.
What I found interesting between Emby and Plex, is that even though Plex has been around longer, Emby actually manages to get the right cover art for movies and music albums.
It's possible that I should maybe have made a different share dedicated to Emby and Plex, that didn't cross my mind till after I figured out my issue.