Yes, differential input still works with single ended outputs. Mess with desmos.com
https://imgur.com/a/pTpNdr2. a and b is the "ideal" or exactly what is coming out of the HU. Signal = ground. Since its a differential input, you use unshielded twisted pairs. That means that noise get radiated onto both conductors. So c and d is a and b plus the imaginary noise I came up with. When you do a-b and c-d, you get the same thing. You mention "balanced", but there are no balanced cables with RCAs in car audio. For a cable to be balanced, it needs to have 3 conductors. Which rcas dont have. Those pictures are talking about XLR adaptors and balanced stuff, which isn't a thing in car audio. I dont have anything to say about those pics