I mean normally by this time in your career, you are what you are. You can point to very few who have ever made the leap this late. John Elway being the first one I remember, but he had success early on by getting to a Super Bowl so not really the same.
The other one that is the comparison that fits is Stafford. A playoff loser. Never won a division. Never won a single playoff game. Choked big time in the 2014 Dallas playoff game. He gets a change of scenery in LA with QB whisperer McVay, surrounded by a front office who loaded up and went all in (not like our fake all in). And won a ring. But he didn't really elevate his play in LA. He was just surrounded by a ton of overall talent and they could mask his weaknesses way better and McVay designed the best offense for him. He tried his hardest to blow the NFC Champ game but SF blew it and dropped an easy pick towards the end.
Dak's skill won't increase but the situation around him could get better. But it won't here, not with this bozo front office. He would need a whole new team at the end of his career.