Apple Music (MusicKit) + AVAudioEngine

I've created an app that applies stereo EQ to songs with AVAudioUnitEQ and AVAudioEngine. It works great on MPMediaItems with no protected assets.

I'd like to apply the EQ to Apple Music tracks for users that have an active subscription.

In order to play tracks with AVAudioEngine, I create an AVAudioFile from the MPMediaItem assetURL. When I try to get the URL of an Apple Music track, it returns nil even though I have an active subscription.

Is it possible to get the URL of an Apple Music track that an active subscriber has downloaded to their library? If so, I think I'd be all set getting it to work with AVAudioEngine.

If it's not possible to get the URL, does anyone know if there's some other method to play Apple Music tracks with AVAudioEngine?