Comparing Dak to Winston is basically deciding between 2 QBs that struggle to read defenses with 1 taking chances and the other checking down a lot. Either way your team isn't going to go far.
I feel the OP question about who will outperform who between the 4 QBs listed: Dak, Wentz, Ryan or Winston. Depends what you're looking for. Dak will undoubtedly put up the best numbers, by far. The defense will allow Dak to check down all day then when we get to the redzone the field shrinks and then who knows. So Dak is a stats machine cuz the defense rarely gets beat deep. Dak will put stats up. It's highly debatable if that translates to winning. In the NFC east, yes that will win, outside the east not so much. So I feel Dak will outperform those 4 by a long shot.
If I had to choose a QB to enter the playoffs with, then my choice is Ryan. Ryan and there's not a close 2nd. JMO on the OP question.