all the penis gags are due to female hyenas have a (relatively) large external structure that resembles a penis. It's not a penis, and doesn't function like one, but led to many stories about hyenas being hermaphroditic.
On the topic of yena winning, hyenas are BONKERS strong. they have one of the strongest jaw strengths of any terrestrial creature. In the top 10 for mammals, iirc number 12 including reptiles because lolcrocsgetrekt
in addition, hyenas are, as mentioned, matriarchal. females are also larger and stronger than males. yena isn't 'acting like a boy', she's 'acting like a female hyena'. this happens to resemble the male dynamic in the more ubiquitous sexually dimorphic species (where males and females look different). the whole 'trap' thing and 'crossdressing' is just a gag to shoehorn it into a manga
let's all try to leave the human philosophical debates about biological imperitavism and social constructs where they belong, not in a manga which is designed to be patently ridiculous