Apple Music is more ‘western-centric’. They do have many mandarin, K Pop, C Pop and Asian music but selection and playlists wise, not as refined as Spotify’s. But of course music quality they’re better as they have spatial audio, Dolby Atmos and Lossless which are really great, especially if you’re on AirPods Pro with ANC on.
As for Spotify, I really love their playlists selection in which they will also display other playlists which are most suitable to your listening pattern or the songs you listen to most, and find comparable genres as well. Apple does also but slightly different. They also have a better range and selection of mandarin/Asian songs as well. Each person have their mileage. And as you know, they cap only at 320kbps.
So if you wish to have overall better song selection, Spotify. For music quality, Apple Music. For me, I use Apple Music solely on iOS, Spotify for both iOS and Android, and Tidal strictly Android due to LDAC support on my Sony WF-1000XM4.