No human can, or would, flush their entire brain to use every single neuron as working memory for chess. By doing that you would even forget the rules of chess. At best a tiny subset of neurons could be used for that.

I wouldn't have expected for anyone to even attempt to argue a human can beat, or even approach, a computer on working memory. Wikipedia is just 24.05gb. You are somehow claiming here that a human can hold that in working memory. That is they read it once and have perfect recall. Not even the most extreme savants have shown such feats.