Sleeving the CAT cable inside armour sheathing would provide mechanical protection.

I do not know what this Small Bore Stainless Steel Flexible Conduit costs but it looks rather tough to chew into.

This Techflex® Rodent Resistant Braided Cable Sleeving makes some interesting claims.

My suggestion was a cheap 200' coil of 3/4" black poly water tubing, commonly used for outdoor water runs to sprinkler systems, cottage wells, etc..

The two chewed bits were very near the two cottages on that side, with the racoons inspecting the outside (secured) garbage bins next to each cottage. So even perhaps just a plank of wood covering the cable near the bins might do the trick.

There's also a chain link fence there, so another thing that might work is to cable-tie the cat5e up a metre or so off of the ground along that run. More sun exposure, but above most ground rodents and stuff.

Run the CAT cable (perhaps also inside the poly irrigation tubing) inside the top or bottom horizontal rail pipe of the fence?