I think if you could see into my brain when I read you would likely see very clear details for rooms and other places, also details for bodies and clothing, but when it comes to the face they would likely not have many features.
I read a 19 book series about a female NPS ranger and I don’t have an image of her face, I have some details, but I couldn’t even suggest an actress to play her in a movie. If a movie has been made before I read a book, I will usually visualize the actors who play each character while reading.
I did read a while ago that there is a fan fiction site that actually creates images of characters in books. I didn’t pay much attention to it, but thought it would be helpful for fantasy books when characters don’t look human.
I’ve been lucky to live all over the US and spent several years overseas as well. This taught me that vocabulary changes by region. Sometimes the level of education has an impact, but I find the community has more influence.