High ping, severely impacting work from home and gaming

Hi all. I am a customer in Northern California with the 1000Mbps plan. Unfortunately, our household has had terrible connectivity for the last three weeks, resulting in reduced capacity to work from home (video chats are a second or two delayed) and enjoy entertainment (ping dependent gaming is impossible). During these times, ping can reach upwards of 2400ms and downlaod speeds to our gateway (using Xfinity's own speed tester) never reach above 90mbps.

 

Attached (and hosted here https://ibb.co/qnk7sLz), please find a pingplotter tracing from a wired computer. A few steps we've done:

 

1. Replaced an older router 

2. Replaced ethernet cords between router/modem and router/computer. 

3. Flushed DNS and reset TCP/IP stack on tracing computer.

 

Any insight into solutions or troubleshooting tips would be greatly appreciated.