Optical is the only hundred percent isolation solution. Now its been reported on another thread Innuos claims optical conversion generates noise that makes it inferior to ethernet. I find that highly doubtful, based on both my experience and many others. On the presumption it may be true in any particular setup, there are a number of variables that may make this possible.
FMC's (fiber media converters) are not of a single quality. You can have generic FMC powered by SMPS, generic powered by LPS, and finally, much higher quality FMC such as the Sonore Opticalrendu line. I have experienced all three levels of optical conversion, Sonore plays on entirely different level.
I've not tried the positively reviewed, and I assume very good performing Acoustic Network Eno, but it, or any filter cannot one hundred percent completely isolate network noise as optical can.
For the skeptics, I only ask they try optical vs. their best ethernet solutions and report.