You won't have to. It isn't happening.
I think the most likely scenario is that we deal with whoever doesn't get Watson.
i.e. - If Dolphins trade Tua in deal for Watson, we're dealing with Jets for Darnold.
I don't believe for one second Jets are keeping Darnold when they can get Fields at #2.
I also feel like Jets could use Foles as a bridge to Fields, so there is potential to include Foles in the deal.
Then we could draft a development QB like Mond, Book, etc in later rounds as a backup/#3.