Thanks for the responses, I think I have solved the problem. It turns out that I had risen to my own level of incompetence, and didn't notice that when Poweramp took me to the settings to grant access, there was a little place on the bottom of the screen that I had to actually select to give it access. When I noticed that and selected it, I can now edit my tags.
By the way, like everyone else, it was a bit shocking to get used to the new interface, but I'm settling into it now and I have to say that I have really loved using Poweramp for many years now. One of the greatest features in the