I am clearly wearing blue and yellow over here, but I think that JJ McCarthy is the same kind of prospect that Mac Jones was.
That isnt to say that he wont become a great QB at the pro level. To the contrary, if he keeps working hard, he has the traits to be a winner in the NFL. But he is the kind of QB that will, at his most effective, be overshadowed by his weapons because he wont be asked to do a whole lot. That is what a lot of people mean by "system quarterback." I just wouldn't aim for that kind of QB in the first round.
He should be a second round QB, but Atlanta or LV could easily take him simply out of need for QB talent. If he falls and Chicago picks up a second rounder in a trade down (and still picks up MHJ - the dream), then hell, sounds good to me. Fields can get better and keep him on the bench, or JJ can win the job with hard work. Just not as a first rounder, please