>Dreaming actually activates the visual cortex, so it doesn't depend on imagination. I thought imagination also depended on the visual cortex. Dreaming and imagining is not too different to me. One is a bit more conscious, that's it.

As I understand it, aphantasia relates to a lack of coordination between different parts of the brain that allows that activation to happen while awake. There hasn't been a ton of research into aphantasia yet, so take that with a grain of salt, but during discussions with other people with aphantasia I have never heard of one of us not being able to dream. Psychedelics work too.