LPSU foe modem and router - how important?

Based on my understanding of your system I think the PhoenixNet will cover any issues coming from your router. You are right to consider everything, it all matters, but your setup looks pretty good. 

I have been heavily tweaking my digital chain lately, with very good results. The latest controversy is the sound difference between Ethernet cables with shields connected on both ends vs those with floating shields vs simple Cat 6 with plastic terminations. But I think I am close to done. ;-)

In my case, switching to LPS for modem and router made a significant improvement, more so than upgrading ethernet cables shortly thereafter.

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.

Computers do not somehow perform their instructions 'better' or 'with fewer errors'. There are NO errors in CPU or RAM or else computer is simply broken. Ethernet and WiFi do NOT lose any bits or else your mortgage documents or family photos could be modified.

Don't buy snake oil. Data centers are all on switching supplies and Belkin cables. NOTHING happens to the data. Hardware and protocols are designed this way. This is not a Red Book CD.

@fastfreight - there is no such thing as 'digital noise'. Network protocols have error correction and are designed to survive nuclear war.