No I think you misconstrue the concept of confidence. Confidence and arrogance are not mutually inclusive. In fact, the most truly confident people choose humility over arrogance simply because they're confident in themselves. People who are typically less than confident tend to put on an added measure of arrogance to go along with their lack of total confidence in the hope that arrogance will make up for that deficit in confidence. Cocky people are always disliked and confident people are not. While it is possible for one to be confident and arrogant at the same time, there is some lack of comfort that elicits that response. More often than not in my 55 plus years of life, I've found that the truly confident people are very humble because that kind of confidence resides deep inside that person and the humility is the platter through which such people showcase their confidence and pride in being. My 2 cents my friend.
I promise you Baker Mayfield is simply arrogant with a facade of confidence and 'I don't give a shit what you think' flair, and Lamar is simply humble and really confident. Lamar is intrinsically humble because his gifts are real and Baker is not because his is pomposity couching his lack of belief in his ability. It may be because his ability is limited. He isn't athletic or big and so he makes up for it with 'crotch grabs' beer chugging, and bravado.