> (100x matmul+tanh?)

Biological neurons are way more complex than that. A single neuron has dentritic trees with subunits doing their own local computations. There are temporal dynamics in the firing sequences. There is so much more complexity in the biological networks. It's not comparable.

You could implement a Turing-machine with humans acting physically operating as logic gates. Then, every human is just a boolean function.

This is exactly it. Biology is making massive use of hacked real time local network communication in ways we haven´t begun to explore.