Yeah the big issue with Hexbear's way of doing it is that it's kind of forced and can cause discomfort to people who don't want to out themselves yet. I wasn't aware they have undecided or any as options, I've never tried to sign up there and have little desire to considering among other things how isolated it is. Even so I don't think their way of doing it is very good since it heavily limits the options people can use, and locks people out of using display names, which are extremely useful. I think a better solution would just be to increase the length of usernames and display names to accommodate users who might want to use pronouns.
Also just want to point out, it does annoy me a bit when people say Agender pronouns, since Agender people don't have a universal set of pronouns. We all have very widely varied preferences and experiences among us. I don't blame you for that by the way, it's a common misconception about Agender and Nonbinary people.
Ah I understand what you were saying now, I wasn't sure exactly and it reminded me of the "Agender Pronouns" thing, glad you didn't mean it that way though.
There are other problems I've had with Hexbear, I've actually been threatened and harassed by several users on that platform, I've also gotten some bad vibes in a few communities there that didn't really make me feel welcome, as a GNC person or as an Agender person. It's hard to describe, it just didn't quite feel right.
But yeah I do hope the user flairs get added to Lemmy at some point, it would be nice to have some of the helpful features from Reddit, like User flairs, and either post flairs or post tags (post tags are probably better since they can federate as hashtags).