NB can be a lot of things. I identify that way because I don't feel male or female, at least not fully. Like if there is a gender spectrum from male to female, I sit around the middle but more towards the male side. But it varies a bit.

The xenogender stuff, I admit I don't really get it either. But if someone is sincere about it, I try and trust that it makes sense to them, and it's not my place to judge its validity. As you say, I think the main thing is to be kind to others and let them try and make sense of who they are in their own way, even if it seems incomprehensible or even ridiculous from the outside