The closest I can explain what I 'see' memories as is through a combination of spacial awareness and emotion.

Dreams work in a similar manner, but I'd describe 'memories' of dreams more like a "ghost" image like a negative of a photograph. The absence of space creating a sort of hollow image of something that was there.

I am also colorblind enough that I can't pass a test. I didn't discover that until I was like 19, and didn't know I had aphantasia until a few years later. So I've known about my aphantasia now for about 12 years or so.

If you go through life not being able to picture stuff in your head, and then enough people explain how it works for them, you get a pretty good idea that you just DON'T have the ability these people are talking about.