Hello everyone, first time on this sub and having a strange issue I’m hoping you all can help with.

As the background for the info. This is a new home, we moved in back in April and had Xfinity come in and wire us a line to the house in May. The line is buried from the post to the side of my house. It then runs up the wall and into the attic above the garage where the tech installed a splitter to connect both lines inside. One line sits in the bedroom unused and the other is in our living room where the modem and router are. The modem/router is the xFi provided one and I also have my own router. We pay for 800 plan.

Now the issue is that we are having trouble with the WiFi. Randomly, wireless devices have major issues getting anything above 10mbps, most of the time just unusable. Then the problem will solve itself and we end up with normal speed. The issue will persist for hours if not days sometimes, then be gone for that same time. Where it gets stranger is that it seems like it is targeting phones and laptops. Our android TVs or PlayStation or Xbox are fine. Sometimes phones don’t work but laptops do, vice versa, or both don’t. Ethernet has never had an issue and maintains top speed the whole time.

The Xfinity “techs” online and on the phone have tried every option with their modem, reset, had me replace for a new one, consistent problems. I have then set the xFi to bridge mode and used my own router, set up how it was used in my previous home, same problems. Reset that and set it up again, still happening. I have combed through every setting 100 times and can’t find a fault. Running the speed test on the xFi or Nighthawk, they both get full speed, over my plan actually, 900mbps. Yet no matter what I change, reset devices, network settings, WiFi continues to suffer and I finally managed to get a tech scheduled for this Friday.

It’s been months of using mobile data half the week because it’s unusable. I have exhausted my knowledge of networking and am at my wit’s end. Any ideas what the issue is? Things I can try? I have read more and ordered a MoCA filter in hopes that somehow does anything and will arrive Wednesday. Thank you in advance.