The bald kid will win cause the old man in the last second will refuse to finish him off or something cause he is after still a child or something like that. Something infuriating is gonna happen, I don’t believe authors will just give old man a win.
If you think about it from his perspective, Gojo went above and beyond to make this costume and when he saw Marin's performance he misunderstood that the only reason his costumes work are because of her, not his craftsmanship.
I remember in multiple interviews Nisio always said that MC in his stories (who are usually boys) are not that important compared to female characters. So it might be the case that Nisin just decided to give Iroha purposefully weak motivation and backstory to let his female classmates shine. But...