So I am in this middle ground, where like you I cannot for the life of me actively picture anything in my mind's eye. I close my eyes and it is black, blank, and lifeless. My wife, for example, can close her eyes and recall my face perfectly. I have read about some artists being able to essentially trace what they are picturing in their mind's eye, though it seems that some incredibly talented and famous artists also have had aphantasia!

Anyway, the middle ground for me is that despite not being able to conjure vivid (or any) mental imagery, I have vivid dreams and daydreams. So it seems that if I am tired or my mind is wandering, some mental canvas unlocks, but not while I am alter and paying attention.