There's no boundary for the system that's conscious. Those chemicals you mention enter into a system that is a thing. Your body,brain w/e.

There's no defined system with llms. A piece of software runs multiplication on various pieces of hardware. There's no thing to be conscious. There's no state or before and after when the next token is predicted. Your response might even be cached. A GPU runs one person's mat mul,then another for a completely unrelated request for someone else. What is the entity that's conscious?