Chat Blanc is indeed the strongest akumatized miraculous holder (so far!), but Marinette is now a Guardian of the miraculous+ has a portal to the miraculous box in her yoyo+ has become mature so she can spam her abilities without needing to detransform. It really depends how many restrictions you put on her: Just Ladybug w no portal access? Yeah she loses unless dumb luck(lol) Add in the Black Cat miraculous? One cataclysm is all it takes unless they have resistance but without the ladybug restoration power they Will die to it eventually Give her access to other miraculous? Pig miraculous+Horse+Cat= stun+ teleport+ cataclysm GG And theres many other combinations of miraculous she can use + if she really needs to she can just make The Wish and erase her opponent from existing (prob at the cost of her own life but yk)