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 app is The 10-band equalizer you get with the pro version. The difference in the enjoyment of my music is amazing when it has been properly adjusted with the equalizer. It amazes me that anyone can listen to music without a good equalizer!
Keep up the good work!