I think that the interior structure doesn't necessarily matter—the problem here is that we don't know what consciousness is, or how it interacts with the physical body. We understand decently well how the brain itself works, which suggests that consciousness is some other layer or abstraction beyond the mechanism.

That said, I think that LLMs are not conscious and are more like p-zombies. It can be argued that an LLM has no qualia and is thus not conscious, due to having no interaction with an outside world or anything "real" other than user input (mainly text). Another reason driving my opinion is because it is impossible to explain "what it is like" to be an LLM. See Nagel's "What Is It Like to Be a Bat?"

I do agree with the parent comment's pushback on any sort of certainty in this regard—with existing frameworks, it is not possible to prove anything is conscious other than oneself. The p-zombie will, obviously, always argue that it is a truly conscious being.