I think that there are a LOT of issues. Plenty before we get to trying to blame it on the quarterback.
I'd start with a defense that can't stop anything. Run, pass, pass rush, can't hold a lead. Not only did they give up the lead with a touchdown, they gifted a two point conversion while they were at it.
They put the offense in a position of zero margin for error.
Then I'd look at special teams that bungled a kickoff that led to a safety and loss of a possession and then blew two extra points.
The quarterback's mistakes are way down that lost
If he doesn't make the plays that he does, the Cowboys are never even in that game.