Normally I’d agree, but Harry Potter is already huge.

And while I think this whole response is a bit extreme, it is a case of her source of wealth being way more famous than herself.

Discworld explores gender a few times in a way that I like.

Monstrous Regiment is about a bunch of women who pretend to be men to join their military. For the most part - these aren’t trans characters, they identify as female. The funny is the characters slowly discovering that everyone else in their group is doing the same thing. One character though, explicitly identifies as male after the “reveal” and has male pronouns used for them.

Discworld as a series tends to be irreverent without punching down. Comedy is a weapon in Pratchett’s hands, but his targets are capitalism and oppressive systems.

LeGuin has a lot of interesting takes on gender. The Hainnish cycle is about a race of humans who had previously colonized a bunch of planets and did lots of experimentation on those populations - kinda Vault Tec vibes. The civilization collapses/gets better, and the POV character is usually some type of researcher/anthropologist looking at how those planets develop The Left Hand of Darkness is a sci fi classic: a planet where people stay sexless until they go into “heat” and will develop the opposite genitals of the person who they are attracted to. There’s lots of switching back and forth. It’s a big deal when the king gets pregnant, because only children the king carries can inherit the throne.

Anne Leckie’s Imperial Radch trilogy is also more gender bending sci fi. Everyone is “she.” The first book was part of the Sad Puppies drama, because it won Hugo’s and absolutely pissed a bunch of a bunch of chuds.