https://www.nfl.com/news/nfl-trade-deadline-information-faq
What is a no-trade clause?
A no-trade clause is a stipulation in a contract that allows a player to reject any proposed trade in which they are involved. No-trade clauses may also feature variations, such as provisions stating a list of pre-determined teams a player is willing to waive the no-trade clause for or one that allows a team to only trade a player during a certain period of time.
You are putting the cart in front of the horse.
@SultanOfSix is correct. Other teams can submit a trade offer to Jerry Jones. You are correct Dak Prescott can reject any trade offer he does not agree with.
Your latest counterpoint involves Prescott initiating a trade scenario, that Jones must agree with, in order for Dallas to submit a proposal to another team. Your alternative is another hypothetical that does not negate the first point Sultan initially made.