Thanks for your response. Actually, they do allow plugins on the .com platforms with the business plan, a recent development I think. I just got it to work for a particular setup. I had to deactivate/reactivate, and it seems I have to uncheck “use AJAX queries”. Also, the duplicate issue seems to occur when I check the “use Album Artist” option. Apparently when a particular artist has multiple albums, and the “album artist” field is used for for only some of the albums, that artist will show up twice in the list. If I uncheck this option, no duplicates happen, but of course I get many more artists in the list.
https://angularbanjos.com/my-music-library/