I am nonbinary but the only options are "male" "female" and "undisclosed". What does "undisclosed" even mean? That's like saying "dont want to say" which is definitely not right. Also, an additional question, how do I edit things about my profile other than the things in "preferences", like, how do I set my birthday or discord link?
To get an answer to that, ask staff. My guess is that Fandom has only 3 options because that is what MediaWiki comes with. If I had to guess why MediaWiki has only 3 options, I would say it is because of the coding complexity involved with handling gendered pronouns. But if you feel up to the task of coding an efficient extension to handle 10+ genders in 20+ languages, be my guest.
and yeah, as Tupka said, they removed stuff like birthday and etc from the masthead, so you can't edit/add those anymore, its just a big text block now for your bio where you can put anything. Tho Discord can be set via the Discord field, theres still an option for that
I mean, you could just put "undisclosed" on the actual settings, and on your profile settings, you could set it as whatever you want. For example, on my profile, I set my gender as "girl" instead of "Female", because I felt like it lol. However, if it makes you uncomfortable to set your gender as "undisclosed", you could offer feedback like Tupka217 said.