Dallas is too cheap to pay secondary players.
Also, I can't see them trading their first when Stephen Jones bluntly said during the draft they needed all the draft picks they had in order to field a competitive team with cheap players(paraphrasing).
Trading a 1st and then handing out the richest contract for a corner seems to contradict that.
They have a QB on a new huge deal, a RB and a WR on newer big deals.
Cowboys know how to restructure to play with cap space but I can't see this deal ever coming to fruition until maybe the season a la Amari Cooper trade .
Dallas is a team that will throw the rooks to the fire and overcook them if need be instead of getting competent vets during the FA period.
As for McGovern, he looked fine in limited play last year as the offensive line was decimated by injury and he filled in for Martin at RG.
But, I wouldn't say he's a clear cut upgrade over Hunt, Kindley or Skura in the interior. He does over position flex but hasn't had a lot of playing time to show he actually belongs.