Noting Mytek AES-EBU covers essentially all of the most common audio resolution, if there any technical reason to believe, that a well-made USB to AES-EBU converter would actually sound better than a straight USB in?
What piqued my interest is John Atkinson’s review of the Roon Nucleus+, mentioning " … I’ve found that a DAC fed data via USB doesn’t sound as “solid” as when the DAC is fed the same data via an AES/EBU link."_
It depends entirely on how well any input is designed. You can only say that what he said is true using the exact same hardware. Using different hardware might yield different results. And those differences will be very subtle unless someone has done a really bad job designing an interface. Consider also the imprecise language of reviewers. His solidity might be my thickness. I’d look at noise floors and jitter as well as listening just so what you hear is informed by what is measured.