I don't think the point of the article is that Dak wasn't the greatest rookie QB ever. In the long run, being "the greatest rookie QB ever" is rather meaningless. I think the point of the article is that Dak did exceptionally well in many statistical categories that define/separate good QB play from bad QB play (as well as lucky QB breaks vs. unlucky QB breaks, e.g. the interceptable passes thrown vs. actual interceptions thrown) for a rookie and also ANY QB. Also that if he improves on a few aspects of his game that aren't yet in the upper tier, he'll be even better as a QB regardless of the individual statistics.
The article was overwhelmingly positive imo, but also provided some legitimate criticism that I think Dak and his coaches would agree with. Dak's mental game is far ahead of schedule, and for that, we should all be optimistic.