Xfinity voice Wifi calling drops and cuts out and I know it's the Xfinity Network!

For the month and a half we have had service, the wifi calling has been awful.  It cuts out, disconnects, and is pretty much unusable.  I know it is the service and not my phone or internet connection.

I happen to have a another Iphone on the ATT network on Wifi calling that works fine and has worked fine for years with multiple models!  Same network, router, everything.  The phones can be right next to each other and I will literally have people call me back on the ATT phone because the service is so bad on XFinity.  The property that I am at most times does not have XFinity internet, it is another provider but ATT doesn't have any issues with it.    

I have an IPhone 12 on the Xfinity Mobile service, verified that it shows Xfinity Mobile (with the wifi signal).  Same for my other ATT phone verifying that it is on ATT Wifi  

I live in an area where either service gets 1 bar in the house so WiFi calling is necessary.  

Looking for answers and the technical support people tell me to "reset my network" on the phone which doesn't solve anything.  I live in Boulder Co if you are looking for IP to voice switch translation area.