Actually, I did! It turns out that the title is automatically displayed when iOS decides the list row is tall enough. The magic number seems to be a height of 68 in my experience.

Whoa whoa whoa, you mean to tell me that MusicKit JS has a .completed playback state and MusicKit itself doesn't?! I'm off to file a FB...

I just ran into this issue and found your post! This is still true as of iOS 26 beta 8, so I've filed FB19990881