The correct cable to connect rica preamp to xor inputs of amp

I have a Rotel preamp that only has analog RCA outputs to the amp. I have a Rotel amp that has both RCA and XLR inputs. In an earlier discussion, someone suggested that perhaps my Transparent cables sounded less than great because I am using soley RCA cables from the preamp to the amp, and that using an adaptor to connect into the XLR inputs of the amp may help, because they are higher voltage. In researching adaptors, it seems to me that there are different ways of connecting an RCA to an XLR. Some, like Cardas, leave pin 3 floating. Others do not. But, I lack the knowledge to determine which is correct or best. In researching Benchmark’s RCA to XLR cables, they seem to recommend connecting pin 3 to the RCA shield for this kind of connection, rather than having pin 3 floating. It seems that leaving pin 3 floating is best for going from XLR to RCA, not the other direction. Any thoughts would be much appreciated.
Here is the link to the Benchmark cables I am thinking about: https://benchmarkmedia.com/collections/cables/products/benchmark-rca-to-xlrm-adapter-cable

Thanks.