Killer performed much better than Zoro and Law in their respective rounds against Hawkins.
The only damage he took was because Hawkins was using Kid's doll as an hostage. Outside of that, he cleaned house with all his dolls, slice through a stronger version of the Straw monster that briefly pressured Zoro(and against Law, he could block him without it), slicing Hawkins' arm off and head defeating him instantly
His sonic attack could also damage Kaido, works like a gamma knife with wider area of effect, and had a better effect on dragon Kaido than Law's ultimate attack
If we add it to the fact he was matching nitoryu Zoro with weaker weapons, far weaker attacks, with less area of effect, he is honestly looking to be at the very least Santoryu Zoro - Law lvl if not superior
However after Zoro's training with Enma, he probably went a lvl ahead, and Law may get a power-up in the battle against BM