Hardware

6c stacks are not a defect, there is no stacking failure that leaves you with only one dead core but a working chip. 6c stack are specifically only stacked for 5600x3d

WTF are you talking about? Zen cores aren't stacked in any circunstance, Zen 3 exists in (planar, non-stacked) 8-core chiplet form, a 6-core Zen 3 chip (5500, 5600G, 5600, 5600X, 5600X3D...) is actually an 8-core Zen 3 chip with two cores disabled.

The only thing that is stacked is the 3D cache on the X3D models. Whether cores are defective or not has nothing whatsoever to do with stacking, because cores are never stacked, they're just ordinary 8-core chiplets.