The OP quotes diagrams that clearly show that incompetent people tend to overestimate their competence, and the most competent people tend to underestimate their competence. Almost all your quoted definitions match that data, so I don't think they're incorrect.

The strawman the OP is trying to dismantle is that people's self assessment declines as they gain competence. Apparently not; from that data self assessment is mostly flat. But a flat line (self assessment) intersecting with a rising line (competence) will still show the symptoms of the common definition of DK.