It's weird to look at passing yards as the best metric here. Passer rating correlates far more closely with winning and, whatever its flaws, is surely superior to passing yardage as a measure of overall QB performance.
Dak doesn't compare as favourably to the average when looking at passer rating:
Dak's passer rating vs top 10 defenses compared to their season average passer rating allowed:
80.7 Avg Allowed Buffalo Bills (86.2 on the road, as they were against Dallas)
91.8 vs Buffalo Bills
85.2 Avg Allowed Chicago Bears (89.4 at home, as they were against Dallas)
83.2 Dak vs Chicago Bears
82.8 Avg Allowed Green Bay Packers (80.1 on the road, as they were against Dallas)
83.8 Dak vs Green Bay Packers
86.4 Avg Allowed Minnesota Vikings (93.2 on the road, as they were against Dallas)
101.4 Dak vs Minnesota Vikings
62.8 Avg Allowed New England Patriots (72.6 at home, as they were against Dallas)
64.2 Dak vs New England Patriots
So basically Dak performed right around the average, maybe slightly above average (though not by much, especially if you start looking at home/away splits), against the Top 10 defenses he faced. Looking at the yardage totals gives the false impression that he performed well above average. Based on this analysis, we have an average to slightly above average QB who wants to be paid like a top performer.