I have fiber in my setup: wired Ethernet -> Sonore opticalModule -> fiber -> EtherRegen -> Shunyata Sigma -> Innuos Zenith. I have not experimented with the wired Ethernet feeding the oM - but the Sigma downstream really brought a nice improvement.
Network components upstream from all this still matter, but not as much. I haven’t done much more to further optimize this due to how pleased I am with the results of the span mentioned above. The SFPs matter greatly and the Finisar models I use disappear better than others I’ve tried. The oM was a big deal because when I added it to the ER it was as if my network stopped doing obvious harm.
A good test is to kill the network while a song is playing. In my case I was able to connect the oM to a smart plug and kill the juice using my iPhone while listening. There’s an obvious improvement in sound quality - though the delta has diminished with all the optimization such that I don’t feel a need to kill the power.