I haven't played around at all with the curator stuff -- @JoeKun, that post is a great overview and has me playing around in Postman.
One thing I haven't been able to figure out: is there any particular rhyme or reason to the order in which the API returns the Playlist relationships? Taking your example of Apple Music Pop, I had expected the API to return the playlists in an order roughly equivalent to the page in Music.app. The most popular playlists first, which as I look now at Music.app on my Mac are "Today's Hits" and "Viral Hits."
These are the two playlists returned from this endpoint, which I don't see anywhere on the Music.app Apple Music Pop page:
"name": "Tom Mann: Songbook",
"url": "https://music.apple.com/us/playlist/tom-mann-songbook/pl.b5a5fecc589d4056be182e8cafdc0fc0"
and
"url": "https://music.apple.com/us/playlist/ivan-dorn-essentials/pl.362b70aa54e54989a08a2e2df4ff48d3",
"name": "Ivan Dorn Essentials",
The Albums relationship for Artist seems to be more or less by popularity, but that doesn't seem to be the case here. Any hints at how to best make use of that resource?