Im not sure its exactly over confidence. Like I am sure its part of it but it sounds like and everything looks like by his actions that he wants his image to be the best. In his mind the best is Tom Brady so he wants to emulate that. Between the articles I have read and the way he has acted in some videos I seen, this stuff all lines up pretty well.
But yes, his skill trait IMO is more so like a mahomes/allen where their best plays come from getting out of the pocket and making unscripted stuff happen. Seems pretty obvious he is too short to stand in the pocket and see the entire field.