I have Xfinity/Comcast as well for Internet/TV/Phone and also use their Gateway, and do not have that in my Profiles. Apparently you can set up a profile to automatically connect your Mac to a Xfinity WiFi hotspot when traveling, but I have never done that. The pictures provided in their article are for an older OS, but the details are the same. In my opinion, I would select it and remove it by clicking the "-" button.
https://www.xfinity.com/support/articles/wifi-for-mac
Xfinity has a network that you may see at > System Settings > Wifi, that is called "xfinitywifi" that is their Hotspot that users can connect to. Every router offered by Xfinity broadcasts this network so other Xfinity customers can connect to it as a Hotspot. Your Mac should not be connected to this network and should instead be connected to the WiFi network that is set up on your router for your own home network.
If that doesn't stop the messages, then post the free EtreCheck report using the Additional Text option when posting. The report contains no personal information, but would show whether the Proton VPN still has files loading on startup that need removed.
Using EtreCheck - Apple Community