Panpsychism is actually quite reasonable in part because it changes the questions you ask. Instead of “does it think” you need to ask “in what ways can it think, and in what ways is it constrained? What types of ‘experience/qualia’ can this system have, and what can’t it have?”
When you think in these terms, it becomes clear that LLMs can’t have certain types of experiences (eg see in color) but could have others.
A “weak” panpsychism approach would just stop at ruling out experience or qualia based on physical limitations. Yet I prefer the “strong” pansychist theory that whatever is not forbidden is required, which begins to get really interesting (would imply that for example an LLM actually experiences the interaction you have with it, in some way).