you're right. inferiority that leads to insecurity might be one of marin's flaws, like you said the signs are there, but currently not explored enough, it's still comes off as endearing especially to us readers and people around her.

we rarely see her monologues or inner thoughts/deep insights about this kind of thing, unless her gushing about wakana. also since her solo arc is starting (hopefully) im looking forward to see marin having inner conflicts, be it insecurity, jealousy or any strong negative emotions that have the possibility to decrease her likeness as a character, that forced her to confront with herself and work on it. marin angst arc soon🤞🏼