I had to look up pantothenic acid as I knew nothing. While we know how reliable wikipedia is as a research source ;) it looks to me like that must have been a really hard vitamin to avoid and a lot of its deficiency symptoms overlap with yours so while if the advice is only three years old it probably isn’t to blame, I doubt its avoidance has helped. I don’t know anything about copper toxicity either but it seems to me that advice to avoid something that’s in darn near EVERYTHING isn’t very useful advice.
There is SO much information out there it is so hard to figure out what actually applies to each of us as individuals. I wish there was just a handbook “Do this and you’ll be fine” that actually was right.