I’m not sure how well my suggestions fit.

• Terry Pratchett, any of the Discworld novels. I really liked Equal Rites. Pratchett does cover serious topics, but in a lighthearted manner.
• Norse Mythology by Neil Gaiman. It is a funny re-telling of the stories aber Odin, Loki etc., which were more whack than I expected.

Why not use good old signatures for that?

It’s not an eiher/or. E.g. non-trans could also be non-binary. So cis is more specific and leads to more inclusive language and thinking.