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.

If I knew precisely which definition of consciousness you are testing against your own experience I would understand your point and I would like to. Can you say what it is that you are sure you are not?