Now Is Your Last Chance To Opt-Out Of Amazon Sidewalk - (your Amazon Devices are trying to share your wifi with other Amazon devices to enhance their "tracking network")

I don't know the exact details: https://www.xfinity.com/support/articles/disable-xfinity-wifi-home-hotspot But I will say if the ISP who supplies access is using a rented device to supply access on a separate channel it's a bit different than a company who is not supplying access opening a gateway to allow other people's products to leach off of your wifi for their "tracking purposes" (especially if you have to pay for data).