Lamb is the #2 WR in the NFL and got paid accordingly. Dak wants to get paid like he is the #1 QB in the NFL and is arguably 10-12 in almost any QB comparison you read/watch. If he wants to stay in Dallas his salary will slot here, if he is only about the money then he will test FA after the season and likely get what he wants. It's really not that difficult, and no knock on him.
Trey's play if anything hurts Dak's chances as Jerry saw enough to continue his development and let it ride this season to see where he lands. Worst case go get a Vet QB and draft one next year. Trey was never and will never be a threat to Dak's time in Dallas. Trey is here in case Dak walks