I totally relate to that feeling of being confused by the mandatory (a)gendering system.
I was assigned as a male, so I socialized as a boy. But as an ace, aro and aplatonic, I never totally fitted into the "manliness" mold (pack mentality, ostentatious displays of power and all those things...). I have no gender euphoria or dysphoria and I don't really "feel" what it is the gender behaviour I'm supposed to perform, so I often consider myself as agender. But at the same time I know that I am educated, behave and look most of the time as a man and don't care at all how people gender me, so I do not feel the need to change my gender expression. Therefore I think (cis) demiboy is the best label for me (and arogender too, I guess).
Usually I don't care at all which pronoun people use for me. That said, I feel very upset (for no strong rational reason), which is unusual for me as I am quite a chill person, when someone changes the gendered language they use to refer me when my gender expression changes. It just don't feel right. If I wear lipstick and a convoluted hairstyle for fun during a party that doesn't mean that I am an other person and I don't want others to make me feel it is the case (but why does it feel such a big deal to me, idk ).