As far as I’m aware, the only ability we know Maxwell used in combat was duplicating the opponent (he duplicated the anti monitor). Everything else he does is meant to just help people throughout the games.
Granted, I image the opponent needing to fight a perfect copy of themselves would be pretty bad (especially since Max’s copy won against the original person he summoned it against). But, it gives Cure a chance to kill Maxwell.
I’ve heard, for some strange reason, dying to the opponent after you already won doesn’t count as an inconclusive (Garou has lost 3 or so matches despite his radiation absolutely killing the opponent afterwards, why that isn’t an inconclusive I have zero idea); so I’ll vote cure. He likely loses to his copy after the fight, but Maxwell summoning the copy gives Cure a chance to easily kill Max.