It's not a hard cap. The salary cap is a virtual myth. You can manipulate it in any fashion you want, pulling money forward or pushing it back, to fit anybody on the roster your heart desires.
The cap is a built-in excuse for owners to keep player salaries down artificially in the "name of competitive balance". I don't disagree with that sentiment because we've watched Major League Baseball become a joke because of the lack of a cap. Each owner receives about $250 million apiece from the TV contracts. That's more than enough to run their entire organization's fiscal budget. Then, they can keep every dollar they earn otherwise from their advertising deals, tickets sales, parking fees, concessions, jersey sales, etc.
Owners are making well over $100 million a year clear.
Zack Martin will be the highest paid guard in NFL history for about 15 minutes. Three years from now, he'll be a bargain just like Tyron and Frederick.
I also think Stephen is done with the big contracts for offensive skill guys. I'd bet Zeke will be lucky to get paid again here (he's gonna be fat and slow in 3-4 years). They HOPE they have to pay Dak. I think the plan is to put the money at QB and up front on offense and defense, then just rotate through the draft for the other positions. I think that's a good plan in general, other than than those truly special guys you identify along the way.