It occurs to me that the Dunning-Kruger effect and imposter syndrome are like mirror images of each other. One is to see yourself as more competent than you are in areas that you know little about; the other is to see yourself as less competent than you are in areas that you know a large amount about. (In both cases, the better alternative is to evaluate yourself accurately.)
Are these things the opposite sides of the same coin? Are they the opposite ends of a spectrum of "the more you know, the more you know you don't know"? Or is the inverse similarity between them just superficial, and there is no relationship between them?
Imposter: “I’ve read up, but man, there’s so much to know I’ll never know enough. People will see I’m faking it.”
PhD: “I’ve read up, have a good understanding of my field and even extended it. I’ve also learned how little I know.”
The first and third have self confidence. The second worries, but probably knows enough to do the work. The third knows whether they should even try, although D-K can occur outside of speciality.
The middle ground might just be the best hire.