It’s difficult for the books to be exactly the same because of various differences (there’s no Night King, there’s another key claimant to the throne etc), but yeah, the books could end with Dany going full-genocide and Bran becoming king and I’d be okay with it, but it will take a lot of legwork to get there. Luckily GRRM seems to be fine with legwork.
And I think it will end up like that tbh, can’t imagine he’d sign off on letting the TV show do entirely it’s own thing.
But you should read the books, they’re very enjoyable.