Isn’t Martindale strictly a 3-4 guy? It would take 2-3 years for the Cowboys to have appropriate personnel for a good 3-4 defense.
I think Martindale is.
Draft or sign a true 1T. Gallimore, Hill, Osa, Watkins at the DT. Parsons, Gregory, Basham, maybe Von Miller, Lawrence, at the OLB with Lawrence able to push inside. Then all you really need a LB's with Cox being one of the ILB. Several variants of ILB in the draft that would work.
IMO, the swap to a true 3-4 wouldn't take but a couple of players, and we need those couple of players regardless of what D is run.