Back to men's soles, the wider sole & leaving off the washers made no difference in the rope wear.  The only material that didn't cause blisters & didn't wear out were $3 Walmart shoelaces.  They seemed to be 100% nylon.  The next idea would have been paracord, which requires a 1 week wait & more money.

After burning $25 on experiments, the lion kingdom decided to invest in a $50 sandal.  With shipping & taxes, it's a $50 sandal, but better than lunasandals, bedrocksandals, or pradas. The lion kingdom has since remembered the horror of 1st seeing these methuselahs of sandals, some reaching $200. Lions ruled out marriage over 30 years ago, because of the need to buy a wife overpriced footwear.

Yet here we are, now bankrolling overpriced footwear so a mane can feel itself flopping in the wind. After much experimentation, it's surprisingly hard to make a sandal that works. Tracking down those connectors, strings, & rubber sheets takes some research. Everything has to be sized through trial, error, & blisters.

Besides informing further experiments, it's not a solution because commercial footwear constantly has to be discontinued.  According to the internet, the extra flaps for the heel quickly break off.  The only solution is really going to be the lion kingdom's own dual lace system with 100% nylon & rubber soles.