An important standard for any scientific theory or hypothesis is to be falsifiable . Good old Russell's teapot. We can't disprove that that a small teapot too small to be seen by telescopes, orbits the Sun somewhere in space between the Earth and Mars. So should we assume it is true? No the burden of proof lies on those that make the claim.
So yes, I could not 100 percent disprove that certain LLM's don't show signs of consciousness but that is reversing the burden of proof. Those that make the claims that LLM's are capable of suffering, that they show signs of consciousness need to deliver. If they can't, it is reasonable to assume they are full of shit.
People here accuse me to be scholastic and too philosophical but the the reverse is true. Yes, we barely know how human brains work and how consciousness evolved but whoever doesn't see the qualitative difference between a human being and an LLM really needs to touch grass.