Issues with Video Conferencing

Hi, I have an 800Mbps plan from Xfinity. The download speeds are always greater than my plan. However, while using any video conferencing platform like Webex, Teams, Chime, Slack, etc. I experience "poor connection," and the connection drops randomly. The video shared screen, and the voice gets frozen for a bit and then restored. It happens randomly but frequently enough that I end up taking the calls from my cell phone to avoid disruptions in conversation. This seems like a packet loss, jitter, and/or latency issue. I have replaced my router, cable from the outlet to the router, and amplifier, and even bought myself a new, more powerful Macbook, but that did not fix the issue. 

I contacted Xfinity support multiple times to get help, but unfortunately, they cannot do anything. According to them, all video conferencing platforms have the issue, but not Xfinity. Instead of trying to help or escalate to someone knowledgeable, I continue to get the same answer.  

I would like to ask for assistance to resolve this issue and am happy to help.