I feel like most successful generalists approach problems from a perspective of "never stop learning" that is contrary to a false sense of confidence.
In other words, my perspective as a generalist is not that I already know enough about a topic (enough to be dangerous), but rather that I don't know many things but know how to learn quickly.
I think there is some truth that being a generalist requires a degree of confidence and charisma to constantly wade into things out of your depth, but without a healthy dose of fear and respect for the unknown, you're likely to get burned before getting very far.
A Dunning-Kruger generalist just seems like someone who has always gotten lucky with projects and has never had to reckon with running up against their lack of knowledge.