Look at the 2 SB teams, arguably the two best offensive lines in the entire league. The Chiefs did not give up a single sack against a defense that had 85 in the regular season. Biggest reason why they beat the Eagles, was cause they were able to run the football effectively. They did this with a former 7th rd running back, where they aren't picking up the 5th yr option on 1 they drafted in the 1st rd. Eagles run game was the best in the business, not only was it hard enough facing a read option QB, but they were able to keep him clean all season long.
If the Cowboys want to return back to an elite running team, it's about shoring up their OL first, replacing Zeke will a legitimate option to complement Pollard. I wouldn't hurt to use Dak's legs as well.
With the news yesterday, Tyron coming back, Steele ahead of schedule, I would target either Ethan Picoc from the Browns who was rated the 5th best center and played under Scott/Solari in Seattle or John Michael Schmitz in the draft. I fully understand Biaz is improving and just came off a pro bowl season, but we need an elite Center to reach that next level.
As for running back, I think with a deep class, we can find a very good prospect somewhere on day 2. Charbonnet, Bigsby, Evans all would be excellent fits.