Here's my best guess at it.
The Cowboys have allowed the 11th most rushing yards to opposing QBs this season. On the surface that's not exactly an eye-popping ranking. But the 10 teams ahead of them have allowed an average of 53.4 total carries to QBs. The Cowboys have allowed just 36 attempts (33% less).
Pretty obvious where I'm going with this. They seem pretty susceptible to mobile quarterbacks, and we certainly have one. We just have to utilize him; something it appears other teams haven't really done much of against Dallas.
We're a run-first team with Barkley. The play fakes need to be flawless, and Jones needs to get outside the tackles and be nearly perfect with his reads (in regards to running or finding an open target). Run that a lot early on. Get the middle of Dallas' defense to be leaning outside the tackles just a little bit. Maybe that'll free up a little bit of space for Barkley between the tackles.
Then with that... stretch the field with the passing game. If the threat to run is there, both with the quarterback and running back, the best opportunity to get big chunks in the passing game is to make it vertical. Slayton and Golladay (yeah, him) need to be at their best, especially down field.
As for the defense? I really don't know. Pollard is so dynamic, so my only hope is the Cowboys fall in love with Zeke after 2 TDs yesterday (both just 1 yard runs) against a team that didn't show up. If they do that and Dex/Williams can bottle him up on early downs, maybe Thibs can have his coming out party on thirds and get us the ball back.
It's a long shot, but that's the best shot IMO.