Malachite would’ve had a significant size advantage, but I think Sugulite could’ve done a better job. Alexandrite is the stronger fusion, but she’s a bit unstable-with Alexandrite needing to keep herself from unfusing mid-fight and all 3(5) personalities not melding together well. Sugulite, though destructive, is at least in sync. I feel you can make an argument either or: Alexandrite is unquestionably more powerful than Sugulite and her and Malachite were nearly deadlocked, with Malachite gaining more advantage thanks to being in the ocean. IF, hypothetically, Sugulite fished Malachite out of the water with her wrecking ball and kept her out of the air, then Sugulite could take the win.