After thinking about their situation I think this is what they should do. First, attempt to trade all expiring contracts you will not sign for whatever you can get. Accumulate as many picks as possible even if you have to stagger and take a 2022 pick to get a better round. That's Griffin, Aldon Smith, Chidobe, Jordan Lewis, Noah Brown, Xavier Woods off the top of my head. Bench/cut Poe and Worley. Start playing all your draft picks from the last couple of drafts.
With all that and a team that has quit you probably lose out. You hope you lose out and Giants, Jax, Falcons, and of you're lucky jets win a few games. Hope like hell 2-14 gets you the 1 or 2 pick. If so you take Lawrence or Fields and tag and shop Dak to teams like Chicago who feel they're a competent QB away from a title run. Get the best package possible for Dak and move on with building through the draft and cap space.
If they don't get the 1 or 2 pick then sign Dak and use the picks to load up on players to build with.