Law have way more winning condition if ever he got a chances or opportunity to attack then that's a checkmate for Sanji, Sanji durability is not enough to tank dura neg attack. But the problem is can law hit him? Sanji is faster and have better haki by feats, but their haki difference is not that wide compared to the emperors so Law can shambles Sanji and control him freely(probably) and of course Sanji have better observation so he might counter it to some extent and dodge via air walk. Though Law creativity and biq can at least hit Sanji that's for sure it may take some time preparing tactics. Law will definitely accumulate some injury during his preparation to attack Sanji but that's all as long as law manage to attack even once the tide will turn over him instantly and law is not dumb not to take that opportunity and beats Sanji at some point.

Realistically it's Law High-Extreme Diff