Both will be equally hard, IMO.
For the Saints game: We are playing in the dome. Teams are notorious for losing in that dome. It's loud and proud and full of Saints fans. On top of that, Kamara will have a field day on our defense. Bridgewater isn't an ideal QB, but he def should not be ruled out when he has Michael Thomas on the receiving end. Also, the Saints have a good run D. Not as big of a worry now that we have a growing passing attack, however, Peyton is a coach that knows how to adjust and prepare his teams for different opponents. This will be no cake walk. I see us winning this, but not as easy as some think.
For the Packers: We will be at home this game. Dak and Co play great at home. Jerry World will be alive. However, Rodgers is an infamous Cowboys slayer. No matter how far behind/ahead we are, Rodgers comes to slay and play. He is no easy foe. They also have a running game and defense now. Add in the fact that our front 7 is playing at a PeeWee level along with only a "decent" secondary, Packers will likely have a field day on us. Unless our offense can overcome their defense, I cannot see us pulling a win with this one unless our defense steps up. Our defenses in the past who have played better than this haven't been able to stop Rodgers. What makes you think this one will?