Are whales sentient? Apes? Dogs? Squid? Alligators? Spiders? Fleas? What's the test? (Yeah, the mirror test - how well do you think that really works?)
H. sapiens has more in common with fleas than LLMs - the LLMs only seem more familiar because they're trained on our text-based interactions. Whatever sentience LLMs do or do not develop, we will be debating how to define it probably until they start reproducing themselves and force us to a sit-down negotiation over how we will divide the Earth's resources - or maybe they won't bother with negotiation.