Personally my threshold for intelligence versus consciousness is determinism(not in the physics sense... That's a whole other kettle of fish). Id consider all "thinking things" as machines, but if a machine responds to input in always the same way, then it is non-sentient, where if it incurs an irreversible change on receiving any input that can affect it's future responses, then it has potential for sentience. LLMs can do continuous learning for sure which may give the impression of sentience(whispers which we are longing to find and want to believe, as you say), but the actual machine you interact with is frozen, hence it is purely an artifact of sentience. I consider books and other works in the same category.
I'm still working on this definition, again just a personal viewpoint.
I read this question a couple times, initially assuming bad faith, even considered ignoring it. The ability to change, would be my answer. I don't know what you actually mean.