I don’t think I can suggest a singular book everyone should read, but I can say which book probably had the biggest effect on my way of reading.
I’m dyslexic and growing up reading was always a challenge, despite doing well at school and university I was a slow and uncritical reader. My girlfriend (now wife) was teaching The Great Gatsby to a class and practically made me read it. The process of reading that book and discussing it with her completely changed the way I read, it was an enlightening and incredibly enjoyable experience. It was as much about the discussions we had about the book as the book itself.
So my recommendation is find a book that you can read and discuss in depth with someone else. For me it has become a delight for us to both read a book and then talk in depth about it. You gain so much more insight.