Xfinity mobile cell signal booster?

The xfinity mobile cellular signal in my area is terrible, always has been.  I've done everything suggested at https://www.xfinity.com/hub/mobile/5-ways-to-improve-your-cell-phone-signal?linkId=125084615, other than #3 (use a cellular booster); the other options did not help.  Very inconvenient when we lose power, it is impossible to report an outage on my phone with only 1 bar of service.  Also, I recently had a new Xfinity router sent.  Without enough cell signal to use the internet on my phone to enable it after removing the old one, I cannot enable the new one.  Is there any way at all to boost the cellular signal at my home?  If not how do I enable a new router?