Your neurons aren't doing anything except spiking in response to action potentials (among other physical processes). They're just producing outputs given some chain of inputs and have no semantic understanding either. Where does the understanding of Chinese (or English) come from then?
Also your assumption of the program not forming any conceptual content, will depend on what exactly the program is doing. The Chinese room says it's carrying out a conversation in a manner indistinguishable from a human, but that could mean anything from running a very fancy GPT-3 to running a whole-brain simulation of a Chinese person.
In either case, the human running the program is a distraction. You might as well ask if the pencil or the book he's using to compute the instructions understands Chinese. If the program was running on a CPU, it'd be the same thing - the CPU doesn't understand Chinese, the program does.
Also your assumption of the program not forming any conceptual content, will depend on what exactly the program is doing. The Chinese room says it's carrying out a conversation in a manner indistinguishable from a human, but that could mean anything from running a very fancy GPT-3 to running a whole-brain simulation of a Chinese person.
In either case, the human running the program is a distraction. You might as well ask if the pencil or the book he's using to compute the instructions understands Chinese. If the program was running on a CPU, it'd be the same thing - the CPU doesn't understand Chinese, the program does.