I know this sounds silly, but reading genuinely never captivates me. I am able to imagine things with my minds eye, but it requires that I just completely focus on picturing something and ignore the book while I do it. I think I just have a bad imagination or just a stupidly short attention span for anything that isn’t a creative endeavor.
When I read informational content (research papers, history, geography, etc) I can straight up read for hours because I end up learning something cool.
My wife can read books for hours, but I struggle to stay engaged. Fiction/fantasy especially is rough even if the topic is inherently interesting to me. Poetry and short stories are okay.
How about reading aloud? I find performing books as I read aloud makes them more enjoyable. Because I’m reading to my kids, I have to read in a way that clarifies what’s happening, and I like doing unique voices for each character so they know who’s talking even if the name is after the speech. That forced me to really understand and imagine the story as in reading.
Another idea is to try narrative nonfiction like popular science or history books with a lot of story telling. The story behind the information can be a bridge to building your imagination.