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.
Do you have an internal monologue? … a voice (your voice) that can say things in your head?
It seems some people can imagine some subset of: visuals, audio, smell, sensations (falling, acceleration) easily… and sometimes it takes people a lot of effort.
I take pauses, a few seconds, after reading a description of a person, event, place etc to build a mental picture and continue reading with that in my head. Once created, my head maintains it as I read on.
If you can’t yet, start with something simple… an ambiance of just a color, a time of day, the smell of soil etc.