Finding an instep cord that can take the abuse is a never ending experiment in your environment and style.
My favorite so far is the small diameter, coated, braided yellow stuff commonly used in bear bagging. For me, on the dry rocky trails of the Winds of Wyoming, and the CT, and CDT in Colorado, it lasts the longest. And it is easy to take a bunch of spares, as they don't take much room.
The big stuff in the photos is yet another test.