Why would anyone pay a 1 though when they know Dallas cannot afford the 50m in cap space? Not to mention even to get a 1 you have to actually tag him and to do that you have to HAVE that 50 million in cap space set aside not being spent on anyone else. All that for a player you want to trade and you cannot trade him until he signs that tag, so he could basically block Dallas out of their entire Free Agency period by delaying a trade and then Dallas has cap space and a future 1, but no actual players for that year because the free agency period ended.
Right now Dallas has 11.2 M in cap space plus count Dak at 31.4M.
50M isn't crazy money provided they don't eat it all year.
The team has been conservative with the cap but could slip a lot of money into future seasons to fit 50M under the cap. (Zeke, DLaw, Tyron)
And when they do move the money they'll just carry a large lump sum over anyways to defray future costs.
A team would do the deal to make sure they won the Dak sweepstakes and got the deal they agreed to actually signed.
A team like Chicago that feels they are a QB away from regular playoff contention would be smart o kick tires on that type deal.
Teams have paid a 1 and 3 for far lesser QBs.