I’ve been trying different methods to do this for several years now. I have two macs with 2 main users, so multi-computer and multi-user on each computer. About 2500 albums/26000 tracks. I tried networked libraries, but iTunes/Music doesn’t like them. Things slowly start to go haywire, lost music files, artwork, random stuff goes wrong. I tried Supersync, but I could never get it to work correctly. Not sure how up to date it is either.
I don’t like how the built-in library sharing works, so I don’t use that. I never tried iTunes match since i heard many bad things about it for people with large libraries like myself.
I tried using regular sync software to automatically keep the libraries in sync, but since Music doesn’t automatically pick up new files you have to manually add them so it’s not much of a savings. And if you change the tags on one mac, the new files get copied over but Music won’t pick up the changes so it’s not a full sync.
I finally just gave up and each computer has a copy of the library. I try my best to keep them in sync. Each time I add music on one computer, I also add it to the other. On each mac I designate one user as the main and add all the music files through that user, and their prefs in Music are set to copy to the library and to keep the library organized. The other user(s) are set to not copy to library and not organize. The secondary user(s) you add music that is already put in the library area by the main user. You need to make sure all the users can read the music files, so you need to do some permissions fixing in the main user’s Music library folders, or wherever you store it. On one mac I have it in the Shared user folder since the main drive is large enough, on the other it’s on an external USB drive. The external USB drive means you don’t have permissions issues between users, but iTunes/Music doesn’t like its library getting unmounted which happens when the mac sleeps, so I have to use Jettison to deal with that.
One annoying issue with the multi-mac/multi-user setup if you have multiple Airplay speakers (i have 6) is that often one person will be playing music from one device (a mac, or directly from a phone, etc) and someone else needs to turn it off, and they have to try to figure out which device is playing the music.
I also got so frustrated with the new Music sync interface to my iPhone that I purchased iMazing to do it. I mean c’mon, can’t they even have the app remember a sorting method in the UI?
Given all the issues over time, I have just recently decided to start using Roon as my primary player. It has a different method - you designate one master library server and everything else is just a remote, but all of them show the same way so it’s not apparent. This also means it’s easier to deal with multi-users and multi-Airplay speakers. But it is subscription. It can broadcast to Airplay, sonos, google-cast, and has its own hi-fi transport method (RAAT) that works with certified equipment, most of which is expensive. If you’re not in it for hi-fi experience, it is probably overkill. But it certainly makes the multi-mac/multi-user situation waaaaay easier to deal with.