Thank you for introducing me to the word Aphantasia.
I've read books on and off. The Lord of the Rings has a lot of scenery description in the beginning of the first book. I gave up reading that series about ten pages in.
The Wheel of Time I read through the years and at last finished the series, sometimes speeding through the books. Robert Jordan the Wheel of Time author would do some scenery description but that would be like three pages of a twenty page chapter. The remaining pages were dialogue/ and an increasing cast of characters as the series went on. With constant backstabs and plot twists to keep you engaged.
Back to Aphantasia: For me I do not have Aphantasia. I can imagine what the author is telling me as I read it. But I don't do it frequently as it tends to slow my reading way down and I end up re-reading what the author wrote just so I can really paint the picture in my head and not miss anything. I visualize the author's words when I want to savor the book and I don't want it to end. Or when I start a new book and I'm introduced that first scene and meeting the very first character when nothing's happened yet and I get to experience everything.
But when I get excited and I end up wanting to finish the book fast, I read faster. When I read really fast I just want to know what happened. Did the villain get killed? Did the villain get away? Thus the words just equal actions and results. It's like when someone asks you is the movie funny and you say, "nah it was just dull and boring".
That balance where authors can keep readers engaged whether its concerning aphantasia or not is the real challenge.