Deku’s AP advantage is certainly nothing to scoff at, and would definitely allow him to win with just a few hits (Heck, if he manages to nail her head, neck or somewhere similar, he could probably take her out with just one good hit, since the 7.5x One-shot gap is specifically for a shot to the torso)
But that’s a two-way street, because with only a ~6x Dura advantage, Connie using a sword means she’s still going to cleave through Deku’s body like butter
so both are capable of putting the other down with very few hits. And realistically, this fight wouldn’t last longer than a minute or two just because of how quickly both can kill/incap each other, so stamina really isn’t that big of a factor. Deku’s pain tolerance also won’t be a major game changer, since he’s going down in one or two hits anyway
And because of Connie’s superior skill and Instinctive reactions, she’s much more likely to get the few hits she needs to win first