We have too many holes. We aren't one player away. This doesn't make sense.
Here's my thinking.
Striking gold with Dak is essentially giving you a #1 pick (possibly two) when all it actually cost you was a 4th rounder.
Your biggest need - far and away - is for a dominant pass rusher.
And Garrett is the surest thing in this entire draft, at least as sure as these things can be. While I wouldn't give up an entire draft, because, as you've said we do have other needs, I'd be willing to part with multiple picks. And that would include next year's #1 pick.
You would still have multiple picks to fill other needs, while having your biggest, most important needs, filled.