First I’ve heard of aphantasia applied to sound / music. Though I have on a number of occasions thought about the concept.

I have (visual) aphantasia. But am better able to remember / hear notes and timbres in my head than images. Never really tried composing and for the number of years I took piano lessons I’m pretty crap at it (lessons don’t matter if you don’t practice in between).

But sounds stick with me more than visuals. So interesting that it’s all on a spectrum with these various facets.