Yes, exactly, that is the most troubling part. It doesn't provide any answers whatsoever but it is ridiculous that they are not seeing this as an endemic problem that needs to be addressed...whatever the problem is, I still don't know. That said, the Apple Care people are not trained professional IT hackers or anything, by any means, they look up the same forums and help lists we do as they are trying to address your problem. The guy I finally talked to was a "manager" and he seemed stumped, he had never heard of anything like this, etc. He is going to get back to me after the internal diagnostics he did are reviewed but he made me nervous when he said that the next thing would be something that might erase my playlists etc, something I want no part of, even though I've back up everything carefully.
I did disable Apple Music and the same problems persist.
Of course, Apple probably did all this on purpose, as I think had been addressed somewhere wanting to force people to buy and download THEIR music and to use the iCloud for everything, rather than import cds or completely legal bootleg music files, which is what I do mainly. So with that assumption, of course they would ignore the problem...they don't care about music lovers with 50,000 music files who don't buy much music from Apple, but rather the idiots with barely any music but who buy all of it...that's the most likely scenario here.
Still hoping something can be fixed though and yes I too was hopeful that an update would repair it but not shocked when it didn't, any now, I don't think we can have any hope in updates...