He needs to learn from Bama QB Jalen Hurts. Last year, he had a great season, but by the end of the year, good defensive coordinators had already figured out his weaknesses. Hurts spent the summer working on the weak points in his game. Early reports from practice indicate that he is doing a much better job with his reads and progressions. Hopefully, he will keep doing that in the season. Hurts worked on his game. Kapernick should shut up and do the same. Go to the Manning camp and hire a QB guru to fix his bad habits, and then maybe he can get a look from the Browns.
I think for the successful ones, that is what they do.
I just read a thing about Brady, where before this season began, he drew up a list of everything he needed to work at that was deficient in his game (using his own experience and that of his coaches) graded them by importance/impact, and works on those specific things during the off-season and camp.
Last year, his major thing was being less effective outside the pocket, so he worked on how to handle that.
I doubt someone like Kapernick is doing anything like that.