Hi Mac Jim,
Thank you for all of the information. Most of my music is on an external seagate 5 tb drive, that is powered by wall outlet as well as the usb hub it is plugged into. USB hub is plugged into a self powered hub that is connected to my M3. This is the 2nd hub. I have a 2 TB stick drive installed in it.
"USB C Hub for iMac 24 inch 2021/2023, Minisopuru iMac USB Hub Support M.2 NVMe SSD, iMac Accessories for iMac M1/M3, iMac USB Adapter with USB C 10Gbps, USB A 3.2, SD/TF, M.2 SSD."
This 2 TB drive disconnects sometimes when asleep. I run diagnostics on that and the 5 TB when there is an issue. I didn't have any Apple Music problems until the update though. I spent 3 hours with a senior Apple tech man, and he said this is a known issue, and they are working on an update fix.