I don't know about "make or break", but it is an important year (I know, they all are).
Dak's first couple of seasons he was more the guy that distributed the ball to the playmakers rather than take a lead role as a playmaker himself. Nothing wrong with that if it is working for the team, but that was the role.
Then the next few years he started throwing more and became more of a playmaker himself. It has led to some dynamic games with the Cowboys putting up big points and big stats, sometimes for several weeks in a row, but it has also proven to be less consistent, and the team has had difficulty sustaining that level of offense all season long.
The next step is to gain that consistency. Obviously that's not all on Dak, but as the guy guiding the ship on the field he is a bigger part of it than others.