I've had the same problem since updating my Samsung Note 20 to Android 11/One UI3. It was needing a rescan after every reboot but for some reason now (maybe an update) it's not happening after EVERY reboot, only sometimes and sometimes the library will be empty even if I haven't rebooted! Sometimes my songs are there, sometimes I need to rescan. It seems to be random.
I saw some instructions posted by the dev in a reply to a review on the Play Store but these have not worked. I tried:
- Long press Poweramp icon, ⓘ (Info) / Permissions / Storage / Allow.. Please ensure "Remove permissions if app isn't used" is DISABLED. Alternatively (recommended): disable Settings / Misc / File Access Legacy Mode" option, then in Settings / Library / Music Folders give the new permission and re-choose folders.
