Just a heads up, on my truck all the wires eventually had the insulation crack (like your gray and brown wires) in multiple places. I believe Dorman has replacement door harnesses. If theirs have better wire/insulation than stock then that would probably be the best long term fix. Otherwise you’ll be fixing wires every few years until you’ve replaced them all.
My left rear door does get a workout though, opened and closed at least twice a day, more if I have to grab stuff from the back seat during the day. I assume the wire failure is related to cycles, so if you rarely open the back door you may go a long time between wire failures.