Techs & Maintenance Team Stumped: 8-12 Minute Micro Outages & Upstream Signal Degradation

I'm an advanced Comcast Business user. My business application is a daily 4-hour video stream where I need a consistent 6MBps of upstream. I am very vulnerable to short disconnections (which interrupt my stream) and upstream signal degradation (which cause me to drop frames, effectively ending my stream).

My plan is 50MBps down 10MBps up in Los Alamos, NM.

I'm currently using the official Comcast Business Cisco DPC3939B router/modem combo, but I've also experienced the same issues on a private Netgear CM500 & TP-Link AC1750 combo which I purchased to test the issue.

I've experienced the issues using Comcast's official DNS (75.75.75.75) as well as GoogleDNS & OpenDNS.

Most days, my connection is fine, but every few days I experience one of the following issues:

Issues

1) Connection drops entirely for 8-12 minutes before coming back up without issues. These are too short to be acknowledged by Comcast's call center IVR automated system.

2) My upstream connection drops entirely to 0MBps, but I still have limited access to other services. When this happens a router/modem restart fixes the issue.

3) My upstream connection degrades, and I stream at a much lower bitrate than 6MBps up. This typically resolves itself after a few hours.

4) A slightly longer outage begins -- I can usually tell this is of a different variety from my 8-12 minute "micro outage" because it will go on longer than 12 minutes. When this happens, if I call the Comcast Business IVR, I get confirmation from the automated system that the outage is "real" (recognized by Comcast) and an automatic 4-hour SLA. I have multiple recordings confirming these "real" outages, and they all seem to resolve themselves in under an hour, similar to a Micro Outage.

Things We've Tried to Fix It

1) Swapping my official Business modem/router with a home tech for another official router/modem.

2) Swapping my official Business modem/router for the Netgear/TP-Link models listed above

3) Home techs been out to my residence multiple times and have not detected an issue; they generally are not here during an actual micro outage event.

4) I was escalated to have direct contact with a member of the Maintenance/Line team, the Network techs who handle the nodes. My network tech contact identified a faulty span cable in my area and replaced it, but my issues did not go away after the cable was replaced (in fact, the number of "real" outages, those acknowledged by the Comcast IVR, went up).

I have detailed logs & timestamps for every outage.

The home & network tech contacts I have are out of ideas on what to test next to troubleshoot the issue. I desperately need an escalated resolution contact at Comcast who can take ownership of my issue and who has access to techs from different teams. Right now, when my Maintenance/line tech sees no issues with the Node, he assumes the issue requires a home tech, and when the home tech sees no issues on his end, he opens a work order right back to the Maintenance team. I've been experiencing issues for over a year and I don't know how to proceed.