My original issue (as reported in this thread) was that, after enabling iCloud Music Library, 1) 99% of my songs were marked as "Removed" from iCloud, 2) iTunes/AM/iCloud deleted songs from my music library. (I had subscribed to iTunes Match many years ago, but not recently). I ultimately restored my music library from a backup.
After updating to iTunes 12.2.1, and enabling iCloud Music Library, 1) 99% of my music is still listed as "Removed" from iCloud, and 2) it appears that none of my music was altered/deleted buy Apple Music/iCloud. I guess that's progress.
After updating to iTunes 12.2.1, and enabling iCloud Music Library, 1) 99% of my music is still listed as "Removed" from iCloud, and 2) it appears that none of my music was altered/deleted buy Apple Music/iCloud. I guess that's progress.