You know what they say about assumptions...
https://startrek.website/post/7337983

You know what they say about assumptions... - Star Trek: Website
Although it isn’t really shown, Odo is nonbinary by definition isn’t he?
He present male and has had relationships with women. But he can present any way he likes.
Eh, the ability to present any gender he likes isn’t what it means to be nonbinary. Presumably anyone in the 24th century has that ability.
I more ment, no gender biologically. Just a single ehm… gender?