Got the parts in today and I noticed the improvement immediately - less noise let's your brain not work so hard to sort out the sound.
I did notice that the port left side green LED on the mRendu did not light up with the FO isolation but it does with a straight Ethernet cable? Any idea why?
Also, Cat 6 patch cables seems to sound better than Cat 5.
Set-up:
CAPS Zuma (Roon/Tidal) > Cisco switcher > FO isolation > mRendu > SOtM DAC/Pre > Hypex amps > speakers