As of iOS 18 this issue is still not resolved

Yes, for example loading large Playlist’s songs can take even few seconds when using MusicKit, meanwhile using MPMediaPlaylist from ancient MediaPlayer framework I get playlist’s items instantly. That makes me think Apple Music app doesn’t use MusicKit under the hood because it is so slow

This has been asked for for over a decade now so probably won’t happen. Just having a simple notification for the song’s end would make my life so much easier