Blue Jean. Nothing special as in not magic. Just a good cable.
FWIW, unless you have transformer outputs, your XLR outputs are not balanced. Close and good enough but not balanced. Parts tolerances and just plain old Physics. If running over about 3M, I would use them though even with their much higher capacitance than good coax. If you want to really understand this topic, I would refer you to the Jensen transformer white papers.
XLR to RCA is not too bad, but RCA feeding XLR is going to give a gain miss-match causing maybe higher noise. Many of the adapters are made incorrectly so be careful.
SOME XLR is louder, some RCA is louder. This is where we have some issues with specs. I thought XLR was pretty well-defined in the professional industry but it seems a lot of consumer products do not follow those specs. Seems they don't even respect the 600 Ohms spec. In consumer it varies from 10 to 50K. That is one of the specs you may trust from ASR. All that may make interconnect parameters matter more as big differences in current.