Cannot maintain consistent connection to Twitch.tv for stream playback

I have been struggling with maintaining a consistent connection to Twitch.tv for watching other people's streams from my home internet, not for streaming myself.

Using mobile data or other people's internet connections is the only way I can get smooth playback and chat interaction, even at 160p with no other devices connected to the network and no 3rd-party background processes to eat up bandwidth, like Steam. Browser console logs while viewing Twitch are littered with GraphQL, AVC finishFrame, and WebSocket errors.

Running ipconfig in Windows Command Prompt returns the Connection-specific DNS suffix as: hsd1.or.comcast.net

Here are a list of steps I have tried to remedy my connections no avail:

1. Using different devices (Samsung Galaxy S10 smartphone, Xbox One)
2. Restarting and power-cycling my computer
3. Checking for newer Windows updates
4. Suspending Windows updates for a month
5. Using a different web browser (Chrome, FIrefox, and Edge) and the separate Incognito/Private Browsing mode on different devices
6. Using dedicated apps instead of web browser versions
7. Deleting cache/cookies, and using Incognito/Private Browsing without cache/cookies imported
8. Power-cycling Xfinity modem
9. Having Xfinity IT send the modem reset signal