Totally understandable; I don't think we can fully understand the human brain, using the human brain. We can understand its principles (firings and chemistry, structure and specialized areas, etc) but otherwise it's a capacity problem.

And while I can't fully understand myself, let alone another person, I definitely enjoy talking with people and sharing thoughts that I realize I wouldn't have had on my own.

Humans appear to intelligenty communicate, however these are just cleverly disguised sound patterns produced by the brain that happen to increase the likelihood of food going into their mouths, and various similar reward attracting mechanisms that make survival outcomes more likely. So human intelligence could be reduced to something like "fancy food-attracting algorithms" using the same fallacy.

I'm kind of on the fence on the subject of whether LLMs could be compared to the complexity of the human brain, myself.

Personally, I'm partial to the higher-order theory of consciousness which postulates that consciousness constitutes patterns of thought that arise in response to first-order mental states. So, an external stimulus produces a pattern within the neural network which represents a sensation, and then if a pattern arises in response to that pattern, that is an experience of that sensation.

Given this framework we could ask whether LLMs experience higher order patterns in response to external stimulus. We would have a clear question to ask which is whether the system can observe itself.