Hello BlackJack, and Thanks for these suggestions. I will give them a try.
Regarding working with Roon Support, I started that process in July and averaging only one email a week - sometimes not without my prompting them for a reply - I have gotten no where closer to a solution. In the middle of that three month process I did get escalated to them checking with the “engineers”, but this is even slower and so far yielded nothing significant.
My biggest concern is not my Album Art, but the preservation of my Playlists. Amazingly, they remain working well. I’d scrap the entire process and rebuild from scratch if I was certain I could reconstruct them.