What's better, one conductor or two conductors for an RCA interconnect?

Perhaps mentioning "KHZ" is pedantic, but it make me suspicious about your experience in electronics.  None of my fellow engineers would write it like that.  As for "deflecting" from technical discussion - it deflects less than bragging about PhD title.
(to be really pedantic:  it is 16k  not 16K)

kHz would be it, but I needed to make the K lower case as the spell check caps it.

That is probably the simple explanation of why it got all uppercased.

@atmasphere AFAIK we should write symbols of units named after person with capital unit letter V, kV, A, kA, kHz, kW etc. but spelled out units with lowercase : volts, amperes, ohms, watts. Multiplier doesn’t change that, so it will be kilovolts, kiloohms, kilowatts, kilohertz. The only exception is when unit contains two words like degree Celsius.

Big Volta’s “V” is for DC Volts.

little Volta’s “v” is for AC volts.

Back to the OP’s question…
When a 2 wire and shield cable is used with an RCA it can have the second wire soldered on the “negative”, the positive, or left completely off.

(On an XLR we would solder it to the -180 side.)

It is kind of like 1/2 a transformer, if we look at it like a twisted pair, so I would suggest that one attaches it somewhere. I use the negative side, but the center pin seems like a valid choice.

I dunno @jumia - I needed an XLR to RCA and was not about to pay money and time awaiting a cable.
 

And it even sounds OK.

The soldering looks a bit rough, but once the end is screwed on, you cannot see it.

So how does the RCA connector accommodate 2 connectors(positive and negative) and a ground wire.

^Twist them together.^

I put together some XLR to RCA yesterday.

On the Neutrik XLR:

• The two clear wires twisted together to pin 2.
• The two blue wires twisted together to pin 3.
• The shield all twisted up and soldered to pin 1. 

On the RCA:

• Clear wire pair twisted (XLR pin 2) to RCA center
• Blue wire pair twisted (XLR pin 3) to RCA shell.
• shield trimmed back, and not touching the shell at the RCA.

On the DAC I split the power and shoved a ferrite core on, with the +V in the one direction and the -V wound the other way.

@jumia Specifically I was using Mogami Neglex 2534… 2x blue, and 2x clear, and the shield.

https://mogamicable.com/category/bulk/microphone/quad/

The Mogami is in a brown jacket, so that the WAF abides it laying on a brown wood floor.

I usually order from Markertech and use the Nuetrik ProFi (RCA) or their XLR ends.
But any supplier carries the stuff.
And Canare and others have the same sort of stuff.