Extremely slow speeds and packetloss (Houston) (Again)

I was hoping I could just repost this post from earlier this year, because this is the exact same situation again: https://forums.xfinity.com/t5/Your-Home-Network/Extremely-slow-speeds-and-packetloss-Houston/td-p/3297464#M314074

This is happening again, exactly as before, and seems to happen every few months. Comcast wastes a lot of their time and my time going through the same process every time and I never get an answer about what was eventually fixed or what was wrong. I spend 30-60 minutes on phone tech support doing worthless things, and then wait another few days before they can send a tech out. The tech comes out, doesn't find anything wrong and says he needs to escalate it higher up. Eventually, I get an automated call about something being fixed in the neighborhood and the connection goes back to normal. This happens over and over and over again through the years.

So my question is how can we handle this better? How can I get this issue escalated to the correct person from the beginning?

This is a hard-wired connection, experiencing 10-30% packetloss, with upload/download rates (on the 500/15 plan) going down to 2.19/0.43. Upstream and downstream power levels are getting up on the high side. Log is full of "No ranging response received -T3 time-out" errors.