Unknowns are not all one thing. Several distinctions are important. I set up a taxonomy of ignorance in the first chapter of my 1989 book, and also distinguished meta-ignorance (where you don't know that you don't know) from ignorance (where you know that you don't know).

Another important distinction is between ignorance about something and negative knowledge, which is knowledge about what we cannot or must not know.

The distinction between ignoring something and being ignorant about it is crucial. It's the first branch in my taxonomy, but also see my blog post on this topic.  And the authors of this paper even argue that "critical ignoring should be part of school curricula on digital information literacy".