I personally don't think Dak can do what you are asking from him. In a decade of football, his best season has been his rookie year. The year where he had one of if not the best offensive line in football and Zeke to shoulder the load with him just having to do the bare minimum. As his load and responsibility has grown the worse the outcomes. As the caliber of competition gets better the worse the outcomes of his play.
Have teams with good but not great defenses won in the playoffs? I'd say yes. Probably not a superbowl but certainly a WC game no? Furthermore, I fail to understand how a bad defense is to blame for an offense literally doing nothing for over an entire half of football? Dak doesn't play defense sure. But he certainly plays on offense and affects the defense when he turns the ball over, holds on to the ball taking a sack and putting the team out of FG range and going 3 and out over and over again. Those offensive miscues and lack of any effective execution is hardly the defenses fault. I'd think that a self proclaimed "high iq" football mind would be able to understand this much.