I don't think the Xfinity router can effectively pick/manage the best connection and seamlessly do the hand-off from the 2 streams. I've noticed that when I lose the connection, the signal strength (even though my device is stationary) goes up and down. Once it settles on a stream, connection re-establishes itself and starts working.

12 Tips to Troubleshoot Your Internet Connection | PCMag Mar 17, 2020 My box keeps losing the internet connection. | AT&T Mar 11, 2017 Lenovo laptop keeps dropping Wi-Fi connection? | Lenovo About three days ago our Lenovo laptop decided it hates the internet. Or, in more specific terms, it keeps dropping the Wi-Fi connection. When you check the Wi-Fi it will show that it can't find any connections. Selecting 'Troubleshoot' fixes it by re-starting the wireless adaptor. It will then show all the Wi-Fi connections available. Selecting our Wi-Fi causes the computer to try to connect Spectrum modem keep dropping internet connection.

Jan 31, 2020

why do I keep losing my internet connection? - Microsoft Oct 17, 2013 Why does my internet keep cutting out?- Tech Advisor

Aug 20, 2012

Troubleshooting Your Internet Connection - TV - LG USA