Best shape of his life was many moons ago. He's more brittle of late and I've said it the past two seasons that his running comes with much higher risks than when he was a rookie. Prescott can't do what Hurts, Allen, Daniels, Jackson and other young bucks can do. He was never really fast to begin with. Whatever he has left to do as the Cowboys QB he will have to do IN (and from) the pocket. And that means a renewed, pronounced focus on the o-line and RB.
Personally, I think the window has passed him by. The Cowboys have fallen back from where they were in 21-22'. The conference and the division are now far more hostile to a potential championship run.