The point is that all the Chinese room is is a play to absurdity. That because opening the box reveals mechanisms that we would not call understanding does not mean the system, the Chinese room does not understand. The neuron comparison is to demonstrate that very fact. The brain is a Chinese room. It doesn't have to be relegated to a neuron, feel free to open the box and show any of us what happens in there that we would call understanding.

>It does not take place in an LLM.

I don't know what else to tell you but LLMs absolutely model concepts and the physical world, separate from the words that describe them. This has been demonstrated several times.