You are explaining this to an Eagles fan so that everyone else in this thread can see what information you are missing.
There hasn’t been a top QB contract without a signing bonus in 30+ years. Signing bonuses are prorated; this is how you can give a QB a massive lump sum without it counting as a massive hit against the cap that year. Even Deshaun Watson’s contract with fully guaranteed salaries still came with a 45m$ signing bonus. That is spread over 5 years. In the event the QB leaves your roster, that money is immediately escalated to hit in its entirety the moment the QB is cut/traded. Deshaun’s contract was years ago, Dak’s won’t be that small. Dak’s contract in 2021 had a 66m$ signing bonus. Lamar Jackson’s contract had a 72m$ signing bonus. Goff got 73m$.
Additionally, Dak still has 40m$ in prorations after this year from the 2021 contract where an extension would delay the cap hits. Again, trading or cutting him next year would add yet another 40m$ to your cap.
It would be roster suicide trading him within 24 months of signing that deal, regardless of how it’s worded in Dallas’ favor