I'm also aphantasic and dream normally. The only time I've been "awake" and been able to visualize anything was the few times when I briefly woke up in the middle of the night and when I closed my eyes I was able to see a room in vivid detail but everything was in grayscale. This has happened multiple times and is probably more connected to being in sort of a "between-state" of waking and sleeping than the ability to actually visualize with my imagination.