I have to say, the more time passes and I move over to Mixx for DJ-ing, the more I notice the utter carnage this update has caused in my music folders. Apple Music streams seem to have replaced all my CD-rips and, curiously, some of my iTunes past purchases as well. And while there are duplicates all over the place, the only files that will respond to a click are the Apple Music d/loadable streamed ones - which, as d/loadable Apple Music files, are DRMed.
The upshot of all of this is that, potentially, if I accept what iTunes has arbitrarily done to my music collection, any CD I ripped last year for DJ-ing with will now ONLY PLAY in iTunes, because you can't play DRMed tracks like Apple Music downloads on anything but iTunes.
Searching for the replaced files, fortunately, finds them in the Music folder still and I have spent the last couple of days pulling across folders full of tunes and diligently deleting the Apple Music ones (the ones with the down/cloud icon).
I'm running to stand still, have to make a special effort to save the music I already own. This isn't on and I'll probably seek better music cataloguing software from now on and buy from Amazon, Google, etc to save opening up this awful program again.