That will be based on points allowed. Much of it will depend on if Tony starts throwing pics. The lack of them so far is forcing other teams into longer drives.
It is not just picks, it is sustaining drives, it is third downs, it is the opposing defense having to account for Dak in the run game, it is him moving out of the pocket after play action
And you can't say how well the defense is playing based on points allowed because they may be allowing those points because they are on the field more and may be tired
There are a lot of factors
At this point you have to ride the hot hand until he clearly falters and then you count yourself lucky that you have someone like Tony waiting