Ping spikes every 10 minutes, very frustrating [SOLVED]

My ping is spiking every 9 to 12 minutes. I'm using a brand-new XB6 and my PC is connected to it by cat6. The cables are snug, the coax is not overtightened, and everything seems like it's working ok. I've reset it many times. There are no other devices connected to the gateway and my speeds are decent (357 down, 72 up). This happens even when I have no programs running on my PC. I've tried calling support and they don't see any issues but in the pingplotter below you can see there's a couple failed BGP hops and you can almost set your watch by how regularly the ping spikes. The connection never hard drops though

My exact same issue can be seen here https://forums.xfinity.com/conversations/your-home-network/ping-spikes-every-11-minutes/6408083ebf58aa7d3c22a16c I'm not sure why this thread got locked, it's pretty disheartening to come across someone with the same issue and the post is locked for no apparent reason

Edit: The PP comments are "Target name www.google.com changed from 2607:f8b0:4006:809::2004 to 2607:f8b0:4006:817::2004" (or other ipv6 addresses). I assume this is google load balancing because it doesn't seem to match up with the spikes

Edit2: disabled windows firewall, disabled router firewall, changed ipv4 dns to 1.1.1.1 and 1.0.0.1, restarted - no luck still

Edit3: hooked up a switch to the gateway and plugged a roommate's pc into it. He's having the same spikes

Edit4: DMed support (thank you @XfinityJamesC !). I think the problem might be related to a reserved IP or MAC address for an old XB6 belonging to a roommate who moved out last week. So some sort of discovery script is looking for the old device at our address and only finding the new one.

Edit5: Remote diagnostics inconclusive, dispatch scheduled, will update tomorrow

Edit6: SOLVED! A tech came out and said it was a transmitter/receiver problem. Honestly, I don't know hardly anything about this, but he said it was supposed to be 30 decibels and we were sending 50 db. He removed some unneeded coax splitters and re-terminated the coax lines (and maybe did something else, I had to take a work call so I missed some stuff). Anyway, it's fixed, and the tech was excellent. In the last two hours, I've had 20 ms average, with just one spike to 300 ms.