I'm not going to comment on the trans debate, but I will say I've always loved the novels, and I have immense respect for JK Rowling's literary talent (I also enjoy her Strike series a great deal).

I think the novels are rightly considered page-turning classics. They are an inspired fusion of detective mystery and school story, disguised as fantasy fiction, with a nice coming of age arc over seven books. The world building (which is rightly in the background) is also inspired and entertaining. Really, I don't see what's not to like about them.

The films on the other hand, I do agree only occasionally nudge themselves above average (Prisoner of Azkaban and Deathly Hallows Part II being the high points). For me, the only person who made an outstanding contribution is to the films is John Williams. I've written elsewhere about why I feel the films fail to match the novels (here, for instance).