My pet theory is that I don't think all humans are conscious (in other words, some perfectly cognitively normal-seeming people are just automatons without an inner experience, like plants or LLMs). Mainly motivated by the fact that a lot of people report not having an inner monologue, and other little hints that I've picked up over the years.
The "inner experience" might be totally optional to fitness, like green eyes.
One step further is to ask how conscious your mind actually is. There is a lot happening on autopilot - and everybody usually checks out for a few hours at night. Maybe consciousness is a rare temporary thing.
I think evidence suggests that humans aren't conscious most of the time. So it wouldn't surprise me if 95% of the time people are just stochastic parrots. But maybe that number is even close or equal to 100%.
Intellectually a lot of humans perform worse than LLMs and a lot of people (most of them) are completely unable to process abstract concepts and basic logic at all. Can those people truly be called conscious? Is consciousness worth something without the ability to reason?
That's called solipsism. I went through it as a lad, I think it's not uncommon.