LLM are definitely not sentient. As someone with a PhD in this domain, I attribute the 'magic' to large scale statistical knowledge assimilation by the models - and reproduction to prompts which closely match the inputs' sentence embedding. GPT-3 is known to fail in many circumstances which would otherwise be commonplace logic. (I remember seeing how addition of two small numbers yielded results - but larger numbers…
To say otherwise is almost the path to sure error, and many terrible historic events have happened in that vicinity of categorization what is and isn't.
Perhaps we should go by what sentience means. To feel. A being that feels. To feel is to respond to a vibration in some way. That is to say, anything that has a signal is sentient in some way.