My post was not about Dak, but the team and salary cap situation in general.
Regarding Dak though, he is going to heavily impact the salary cap with dead money regardless of when he leaves the Cowboys even if even finishes out his current contract because they added voidable years on to the end to spred out the cap hit and those will accelerate.
I do not expect the Cowboys to release Dak until they have another franchise quarterback (interim or rookie) to replace him, so that will likely end up influencing when (or if) they ultimately release him (or trade him with his approval).
Because the following year's contract is guaranteed a few days after the start of a new NFL season (in March), at best they will absorb a full season of salary (plus remaining upfront money of course) hit if they release him before his contract ends.
On the bright side, if they are going to release him before his contract ends, we know it will most likely happen between the end of the season and March (depending on when the new NFL season starts) so they can avoid an extra season of dead money salary which becomes guaranteed.
At this point, the smart money move for the Cowboys is to start trying to find Dak's replacement and if they do at some point, then they bench Dak rather than release him since it will likely cost them more in salary cap space to release him (due to accelerated remaining upfront money) than keep him as insurance.