Hello @cantorgale , Like you, I have addressed noise upstream in my digital chain, albeit without fiber isolation. My Router with SWPS (fed) a JCAT M12 Gold Switch with linear power supply, which feeds a GTT AUDIO Switch X with its own custom power supply. But, I had a Sean Jacobs DC4 / AR6 from a previous project (powering an Auralic Streamer) so I repurposed it to power both the JCAT switch AND the Verizon Modem. It did improve things. My TV became clear from the feeds directly from the Router, and sound improved a notch as well. An expensive power supply for sure, but I would probably only get 50% of what I spent on it so using it like this made sense and made a difference! The trickiest part was the plug input on my Verizon modem, which was indeed proprietary, but Joe Kubala figured it out and made a custom DC cable for me to power both the router and my switch.
As an aside, stacking two switches in my digital chain was clearly better than either one by itself.