I’ve read tons of these and still have no idea if I have aphantasia or not. I can’t understand whether people just have different ways of describing what’s in their minds eye or if there’s really a fundamental difference.
YMMV, but for me, the image on en.Wikipedia <https://en.wikipedia.org/wiki/Aphantasia> made it easy for me to understand. That and having a frank conversation with someone close to me: "Wait, you just think of something and see it, like a picture or real life?" "Wait, you actually see anything?"