Dak was the highest-rated QB against the blitz in 2017, when he was one of the worst QBs in the league. When he sucks, which is pretty often, he’s still generally among the higher-rated passers against the blitz.
Blitz doesn’t mean pressure. Once you learn to distinguish the two, then you won’t be confused. Defenses may be blitzing, because they are trying to generate pressure out of desperation.
Great QBs are generally blitzed more selectively, otherwise their numbers would go up, because your exposing your backfield more to less defenders.