I think most will understand and empathise with people who are truly intersex in terms of genes, gonad anatomy, or sex hormonal profile.
One suspects that the vast majority people 'identifying' as 'non-binary' or 'gender fluid' will not be intersex. They will be genotypically and phenotypically male or female. So their non-binary element is entirely supratentorial and cognitive-emotional. So, if we accept this, by extension one might be able to identify as an entirely different species.
I am going to declare as a giraffe.