The DK paper is not about assessing one’s self. There was a self-eval, but the primary methodology used for most of the data & conclusions was to rank one’s self against the others in the group! You are spot on -- this ranking is a major problem for the credibility of the paper’s narrative. Being unable to rank against others precisely, especially when you don’t know their skill level, does not demonstrate that someone is unaware of their own lack of skill.

Thinking that you are better than the actual pros is the easiest to spot indicator of lacking self assessment, so.

DK did not measure any actual professionals.

Thinking you know enough to critique others is a self-evaluation.

DK did not measure whether people think they know enough to critique others.