Ping Spikes Across All Network Devices

Hello, I have been having ping spikes/packet loss for at least two months now although it may have been an issue before, but wasn't nearly as apparent before.

Here is the run down:

• I'm using a wireless connection because I'm on the third floor of my house with my router & modem in the basement
• The ping spikes occur across all network devices suspecting me to believe there is nothing wrong with the devices
• The ping spikes occur in the basement next to the modem/router suspecting me to believe distance isn't the issue
• I ran tracert google.com and the ping spikes were occuring on the 2nd hop which is Xfinity
• I have talked to countless agents and have escalated numerous times for them to say the connection is perfectly fine

I discovered out my modem was using the infamous Puma 6 chipset notorious for ping spikes / latency issues however, I switched modems without this chipset, and the ping spikes remained. I also created two networks to test if it was someone using all the download or upload bandwith, and only had one device connected, and ping spikes remained. Any thoughts on what this could be?