I wonder if the designers of cold war soviet planes read the same color theory because their cockpits are always a very particular indescribable shade of green. There were also very specific colors for subsystems, yellow for fuel, purple for hydraulics etc. Much more than the contemporary US designs.
My father was a mechanic and crew chief working on F-14's during his time in the air force. His two takeaways from his service were: 1. No one should ever join the military for any reason ever forever, and 2. Somebody needs to color code literally anything.
He talked about how the wiring schematics were a maze, made worse by using only non-labeled gray and black wires with connections and mounts that were the same color made of the same material.
The exterior being gray makes sense - harder to see with human eyes. But internals? They should be massively contrasting colors for every single series of pieces to be removed so you can just follow along by color.