Incessant uncorrectable errors

I have the highest internet tier offered for my address, I have a Netgear CM2050V modem, which is working perfectly.  The cable to my modem is brand new, installed by Xfinity business tech.  I have a MoCA filter installed correctly.  Quite often, my service is fine.  When online gaming, I experience up to 5 minutes at a time with major packet loss, which makes games unplayable.

I have had techs here, I have had people do some kind of test on my line from wherever they are.  Sometimes they say there is a line problem, but whenever a tech is at the house, it's amazingly perfect.  That's because my connection is perfect, and the issues are upstream.  I get no help from onsite visits.

The errors occur almost every night (highest traffic period), and there may be a weather component mixed in there.  I have other things to do beyond monitoring your connection.  I know another user who has nearly identical problems a couple of miles away.  That connection is perfect as well, a tech was just out there.

We both have these masses of uncorrectable when gaming with our owned modems.  I have a hard time believing that some mysterious connection issue in my house has anything to do with these errors.  I have had intermittent issues with signal quality for years now, but it has not gone away.  It almost seems like customer service's primary concern is getting the ticket closed rather than fixing it.

I have been told the issue is my modem, I have been told the issue is not my modem.  I have been told my wire is bad, which is idiotic.

I am willing to work with xfinity to figure out this issue, but I can not seem to get in touch with someone from plant operations that can actually comb the connection and find our shared issue upstream (I'm assuming there are people who do this at xfinity).  

I dont think pressing a button at an operator's desk is going to find this problem, but what do I know?  Maybe just oversold?