To those who've been there, original harness, am I fighting a loosing battle?

[TitusDH]

My harness crumbled to dust by even looking at it. With large sections of bare wire exposed. Replaced all of it in one go.70+ years old bullet connectors would not even detach without breaking.
If you leave your harness alone, you'd likely get the idea what burning loom smells like rather sooner than later. IMHO, it is really asking for trouble.