I got my RCA ends for coax from Skywalker, so I'm not sure I would apologize for buying them from Amazon.....

The point I was making has to do with adding connections- if the cable ends make one connection on each conductor, it's theoretically more likely that adding another connector will increase the likelihood of failure.

Also, stacking two connectors adds length and the possibility that something will be stressed- subwoofer plate amplifiers often have cheap RCA jacks, even if they're expensive. I have repaired many, but I doubt yours are damaged since the Coax doesn't produce hum.

You posted "This run is about 60ft and the coax isn’t suitable (loss of signal over the distance)" earlier- To prevent adding cost and aggravation, I think measuring the coax for shorts is a good first step- do it with the RCA ends and without- you may find that they're not making good contact. If not, you have the option to use different adapters or replace the F connectors with compression RCA ends. If the cable shows resistance on the center conductor, a little can be overcome with the level controls.

If you have a TDR, you may find that the location of the problem is accessible.