Challenges with MusicPlayer Singleton for Overlapping Songs and Volume Fading

I'm working on an application that aims to deliver a DJ-like experience by overlapping songs and implementing volume fading. During development, I've encountered a roadblock due to the MusicPlayerController singleton behavior in iOS, which seems to only support playback of one audio stream at a time and doesn't support overlapping of songs or fading volume between tracks.

I understand that Apple Music content is protected and that playback through Apple MusicKit must respect the DRM and licensing agreements. However, I've noticed an application called "Mixonset" that seems to be able to stream songs from Apple Music, use the music player, and create an overlapping effect of songs for users.

Could anyone share insights on how Mixonset might be achieving this within the constraints of the Apple MusicKit? Is there any approach that I could explore to implement similar functionality, such as overlapping songs or crossfading while adhering to Apple's guidelines and without violating any terms of service?

Any advice or direction towards documentation and API capabilities that could support these features would be greatly appreciated.

Thank you for your assistance.