He was never a smart quarterback, or a skilled thrower. He was always a skilled athlete that played QB.
I really hope he can get the right QB building coach. He really could benefit from a Dorsey type when he was a QB coach.
Would love to see him take a year behind another starting QB. Maybe a year or two off - he was always raw as a QB.
But like you said, his head is swollen as a former MVP. He won't be a backup. And for that I hope he fails until he's ready to be humble.