The 3 mods listed all seemed to come from the Nexus half of things so I tried to troubleshoot some & deleted the Override folder to see what would happen, the result was all of the mods from the Workshop suddenly appearing in the list.
Well when I got em all ready to go & checked my mod manager in-game there were only 3 mods listed, which was less than I had from either source individually. I assumed that all the mods from everywhere still just went into the override folder, so I picked some Nexus mods (via their new Vortex client) to go w/ some Workshop mods & assumed they'd all cooperate (as long as they didn't conflict obviously). In any event, I've had a series of confounding issues today. I guess I'm out of the loop on POE2 modding, since last I was messing with it we were still basically doing it by hand.