Might want to look into your router, either replacing it or changing the settings. You don’t get “Wi-Fi” service from xfinity, they give you internet through a wire and the router puts off a Wi-Fi bubble, the same way you don’t get “cordless phone service” from the phone company, they just give you service to your house and you plug in your cordless phone which handles the wireless part.

Especially if you live in an apartment or crowded area there are probably many other routers around you. They work on channels and if a lot of people are using close to the same channel they interfere with each other. So you should go into your router settings check things out. If it has a 2.4ghz radio and a 5g radio sometimes connecting to the 5g instead will help…but it doesn’t go through walls quite as well if you have a big place or brick walls or anything like that.