To add…if I am not mistaken, toslink will result in synchronous clocking meaning your DAC clock will synchronize with the digital signal that’s output of your streamer or transport. Same goes for SPDIF. So whatever jitter is passed from BS streamer clock to DAC will impact the final result. Even with Esoteric.
With USB, the process is asynchronous, meaning the DAC’s clock, in your case Esoteric, is going to get the priority. I’m pretty certain your DAC has a clock that is superior to both BS and Aurender if the latter is a lower model without OCXO clock.
You can’t bombard your DAC with jitter and expect the same results as you would get with a clean signal.
It isn’t all simple and there are factors both internal and external that will affect the sound.
As to Ethernet cables, I’ve tried several and they all work but don’t sound the same.
I’d say Ethernet cable is probably at the bottom of the list with components and room acoustics as well as clean power well above network crap.