Luffy has the best raw strength as he fights with unarmed without relying on magnetism or steel, just rubber stretching. Steel / metal > rubber toughness already. Kid's metal arm already has headstart advantage against a rubber arm.
Kid might have the second best raw strength after Luffy, however, magnetism levitation also helps Kid's physical strength a lot when he pulls or push things with his arm, so he isn't stronger than Luffy, Luffy has the best strength feats with G3.
Luffy reshaped Chinjao's head with G3, overpowered Admiral Fujitora's sword, when Luffy wasn't using Advance CoA or CoC.
Even without advance Haki, Luffy's G3 feats shits on Kid's Punk Gibson, Kid also has magnetism amplification on his attacks, not only physical strength.
Luffy, without even using G3, one-shotted Hajrudin and Bellamy, Kid can't do that shit without using a giant metal arm Punk Gibson, which also has the power of magnetism inside of it.
Why even put Zoro in here, when you talk about raw strength? Zoro can't do shit about penetration or destructive ability without magic swords like Enma, Luffy and Kid don't use special weapons like that.
Law is also irrelevant, and he not only has mobility, he has other kind of versatility advantage over others; gamma knife, radio knife, mes, counter shock, injection shot, giant rock throwing and burrying his opponent in rocks etc. Law is the most versatile fighter.
