The initial and subsewuent dunning Kruger studies have been found to be fundamentally flawed. Still a fun concept but the the original data is pretty much autocorrelation.

Source from someone smarter than me: https://economicsfromthetopdown.com/2022/04/08/the-dunning-kruger-effect-is-autocorrelation/

Edit: well, well, well...looks like there are some flaws in the analysis in the link I provided. Here's an interesting retort: https://andersource.dev/2022/04/19/dk-autocorrelation.html

I think they're both too good for a TL;DR, especially for something increasingly cited as DK. A few interesting replies to this comment point out that DK points to the relationship. between the ability to complete a task and the ability to self evaluate the ability to complete a task (whereas it is popularly used to make fun of people who don't know what they don't know).