The pass rush will definitely be key. They'll need to force turnovers.
I'm not afraid of Ryan because he lacks mobility and he's been known to throw back-breaking interceptions in big moments. I'm more afraid of Prescott because he has the legs to move and a great o-line, but he's also a rookie who has a world of pressure on him to succeed.
Ryan has more weapons than he's ever had and a better offensive line. Yea he isn't mobile, but there have been a number of games where our pass rush struggles to get pressure without blitzing and blitzing that Atlanta offense would be very very risky given all of their weapons and our crappy secondary. Don't get home via the blitz and suddenly you have Julio Jones and other big play guys in one on one matchups without safety help over the top.
As for Dallas, i agree they also pose a myriad of problems for our weak defense. Elliot could gash us for big gains and it would be hard to get pressure on Prescott, who can avoid that pressure when it does happen. Sure he is a rookie and maybe playoff pressure gets to him, but i'm skeptical of that. He's a young guy playing for the glamour franchise of the NFL and it's been a non-stop media frenzy most of the season about whether he keeps his job when Romo got healthy, yet he hasn't flinched one bit.
FWIW, i'm not saying the Packers can't beat either team, just that very likely our offense will need to put up 30 plus points to win because both teams present huge problems for our beat up and low talent defense, if they first beat New York.