see, the thing about mingyu is-- yes he's buff. it'd literally take Such disproportionate motivations (like. the Drive to win) for him to even have the CHANCE of winning over JUN in a FIGHT

like jun has him beat in technical skill (actual martial arts), mischief (thinks it'd be funny to brag that he won so he Will), flexibility (both literal and in identifying what Can be a weapon)--mingyu's best chance is either a surprise takedown (not a high possibility of success) or he is coming after jun with the intent to Kill (not a high possibility of happening in general)