Use the draft to fill positions that have a high success rate. Use free agency to target difference makers.
If there is a player that is a generational type talent, take him. But also prioritize the positions that are more important. Running back is important, but there are a lot of teams that make due with committees at running back. Look at the Chiefs. WR's are important, but nowadays it seems like scheme is more important. You have to develop strong lines. Right now Dallas does not have a strong offensive line or a strong defensive line. We have some pieces but not enough.
Develop a system that works and draft players for that system. If you want to be a road grading pound the ball team, draft and sign players that fit the mold. If you are gonna run a zone defense, don't target man corners. It's really not that hard.
People talk about Barkley and how he suddenly is unstoppable. He didn't just somehow power up over the last year. He went to a team with one of the best offensive lines there is. Same with Detroit, their O line is opening holes for whoever is in the backfield.
Our glory days were tied to having the best OL and DL. We prioritized those positions. It was successful. Fads come and go, but building the lines never goes out of style.