Part 2: From Mac Resources Forums
Steps from jsoto last yr (Jan. 16, 2021):
This worked perfectly for bringing my High Sierra iTunes library (that was on an external SSD hard drive) over to the new Mac Studio running Monterey-- and it worked to keep my Media and Purchases Apple ID tied to the Music app (separate from my different iCloud Apple ID). Just follow his steps-- THANK YOU jsoto
And yes, also make sure that you Get Info (Command I) on the external hard drive and click ignore ownership on this volume. Thanks Fishrrman!
1. I de-authorized my M1 MBA on the Music App, then signed out of my account within the Music App.
2. Once that was done my iCloud Music Library was gone which is what I wanted.
3. I manually deleted the playlist names that iCloud Music Library left in the Music App.
4. Deleted the Music directory under ~user/myhomedirectory/music/music (it gets confusing because Apple Music App uses 3 directories with the same "Music" name.
5. Emptied my trash can
6. Copied my iTunes folder from my Mid 2010 MBP 15 i7 on macOS High Sierra to an external drive.
7. Then from the external drive copied the iTunes folder the the desktop of the M1 MBA
8. I option-started the Music App and selected to "Choose Library" option and pointed to the "iTunes Library.itl" file and it imported the playlists, artwork, etc.
9. Then opened the Music App, followed by Preferences, under "Files" changed the music media location to the Music folder created from within the "Media" directory created by Apple Music App.
10. Then proceeded to consolidate my library by having Apple Music copy iTunes Media over to the location I specified in the Music Preferences by using File/Library/Organize Library/Consolidate Files. It then copied all my iTunes Media over to it.
11. Sign into the Apple Music App with my account.
12. Authorize my computer.
13. iCloud Music Library, iTunes Match, Apple Music subscriptions activated with my sign-in and computer authorization.
14. Zero issues with Apple Music App. Everything in working order.
15. Delete the copied iTunes Folder from my old MBP from the desktop of the M1.
16. Empty the trash.
17. Enjoy Apple Music App to learn the changes from iTunes.
Music and Photos are both working and have my 25+ years worth of content, albums, etc. So far everything is in working order!