This video breakdown highlights a lot of what people have been saying. Frederick is not who he was. Martin is not who he was. Tyron Smith is not who he was either. All true. But the 2019 video shows something else. Almost every play shown in this video from 2019, count the bodies at the LOS after the snap compared to blockers. Both Philly and the Vikings put one more in the box than the Cowboys had lined up as blockers. If the Cowboys offensive linemen can;t win their one on one battles then there will always be a free defender to make a play. Also, watch how fast the Vikings LB attacks the LOS after the snap which overwhelms the offensive line. Compare the Vikings LBs filling gaps to how the Cowboys LBs play well off the LOS and are slow to fill the gaps. This is why how many in the box before the snap doesn't always matter. Having extra guys come down and attack the gaps is how they play to stop the run.
The Cowboys offensive line was losing 1 on 1 battles against the Vikings front 4. It was actually worse against the Jets. I guess the question is, why? Its not just technique. Its as if the Cowboys OL lacks strength which may be the case for Frederick who ise dealing with the after effects of GB syndrome. Martin has back and knee issues which could prevent him from getting the kind of leverage he'd like to get. Connor Williams is still not strong enough. Tyron Smith is dealing with knee and back issues and Collins is dealing with the same. Consequently, the Cowboys are getting out-muscled at the point of attack. But they are pass protecting pretty well.
So what do you do about this? One thing is to recognize the limitations of the front 5. They pass protect better than they run block. Maybe against the stronger defenses it would be smart to throw more on 1st downs and key situations, like 3rd and 2 inside the red zone. It is what it is and I don;t think the offensive line is going to just flip a switch and suddenly block like supermen. The coaches have to play to their strengths, not stubbornly press a weakness hoping it works.