Assuming this is still under development, I thought my experience might be of use.
I input The Three-Body Problem (Cixin), Sapiens (Harari), Leonardo da Vinci (Isaacson), For Whom the Bell Tolls (Hemingway), Bluebeard (Vonnegut), and On the Shortness of Life (Seneca) and received in return...children's books!
Age-gating the recommendations might be something to look into.
[1] https://www.wired.com/story/the-us-hitches-its-final-ride-to...