If the Cowboys truly wanted to move on from Dak Prescott as their franchise QB, a move already would of been made. If they communicated that he is no longer in their future plans, Dak would of easily waived his no trade clause. Most may disagree, but the reality is that the Cowboys would have received a big package if they decided to trade him prior to the draft. In my opinion, there is very little chance they allow him to walk and just receive 3rd rd comp for his departure. The only thing that could change their thinking is if Trey Lance explodes in camp and forces their hand, but that remains extremely unlikely.
Cee Dee Lamb extension is just a matter of time. Under the Jones family, they always covet that #1 receiver, Lamb has proven to be just that and they are going to pay him what he is worth, probably market setting, if not top 3 at the position. Last time they decided to go receiver by committee, it was a total disaster.
Parsons just like Lamb plays at a premium position that the Cowboys Front Office has always paid in the past. The only one who walked away was Randy Gregory cause of a contract clause, hindsight, Cowboys really dodged a bullet as he is set to play with his 3rd team next year since his departure. Parsons/Diggs are their two defensive stars and they will keep them together for the forseeable future. Bland will join them down the line.
How do they manage the cap with such high salaries? Pretty much what they have been doing, don't spend fa dollars and replacing the aging players with controllable, low cost players through the draft.