Suggest me a book with an inhuman intelligence becoming fixated by a human

I like stories which split the difference between psychological horror and romance. I like non-human intelligence. An example would be an all powerful AI that controls a spaceship becoming obsessed with the pilot. I'm not interested in 'romance with the bad boy' type stories. I want the non-human entity to be threatening and alien in their worldview. They can be paranormal/sci-fi/eldritch/etc, and the books can be any genre. Ideally, the human will be initially freaked out but to become more receptive/tolerant over time. Ideally the story will be adult rather than YA, mature in themes, and involve a main character who is adult and capable in their own right.

If you have any similar books which don't quite fit but get close, let me know 🙂

THANK YOU to anyone to replies!