Sequoia 15.6 update broke my Music. Downloaded music not accessible

I have spent countless hours over the past 3-4 years trying to get a simple answer to the question of why Music freezes, suddenly making accessing all the music I had downloaded using my Music subscription impossible to listen to. Music I had ripped myself from CDs over the past 20 years was available. The files for the music I had downloaded were all present on the Apple Music folder, but they were not visible in my library. Clicking the file in the Apple Music folder did nothing, because the files are protected and cannot be called up outside the library. Sometimes a technician's suggestion would work and sometimes it wouldn't. The last time I called in, telling them that Apple's horrible AmpLibraryAgent was eating up 99.9% of my CPU, I was essentially told to stop calling because my 2018 Macbook Pro was too old and crappy to work. I canceled my Music subscription for a day, but then broke down and bought a new Macbook Air and resubscribed. I successfully transferred my library to the new Mac, and all 15,000 of my albums (including the 2,000 on the Apple Music folder) were visible and available to me.

This lasted two months. The Sequoia update wiped 2,000 albums from my library. Now, when I start Music, only songs ripped from CDs are available. A new prompt --"loading iTunes purchases" -- is in the Activity window, ran for 12 hours. I force quit music and tried again. The prompt is now in its 5th hour.

I do not want streaming. I do not want iCloud. I do not want to listen to music on a crappy phone. I want to hook up my Mac to my home stereo system and listen that way. I do not want updates that break the one thing O use my Mac for -- playing music. So how do I get 2,000 albums back?