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.
I think it’s just practice! You’re used to reading factual information, and you’ve got accustomed to it so fiction seems hard work to focus on.
But you can read poetry, so clearly you do indeed have the ability to use your imagination and think/feel when presented with the written word.
I like the idea of one Redditor of trying audiobooks, as the extra dimension of voice, tone, and acting skills can bring out the story more and engage you more deeply.
If you find this works for you, then try reading again [from a book] and it may then be easier.