If it means "not too bothered by the gender of their own meat-suit as they are confident in themselves and their sexuality and feel no need to identify by their gender and its stereotypes - particularly if the change is temporary so they don't need to adapt to an entirely different biology", then I think "gender apathetic" would be the average mindset (assuming they have healthy surroundings not pressuring stereotypes onto them). Few people makes their gender into their own identity (though there are some), and instead ppl tend to view themselves as individuals defined by their identity in some recursive manner.I like 'gender apathetic', haven't heard that one but it's a word that I definitely needed to know.