Graphene on Pixel 4XL - Trouble using Wifi Calling

I’ve been having trouble with my phone connection when I’m home (including garbled speech, can’t hear me, and dropped calls) for quite a while and it’s getting to the point where I won’t be able to stick with a deGoogled phone if I can’t make calls from inside my house. Outside my house it seems to work fine, so that leads me to believe it has to do with the fact that I have only 1 bar for cellular inside my house. I used to use wifi assist with my iPhone, so I looked for a setting and was happy to find a toggle switch for ‘Wifi Calling.’ To my dismay, the toggle won’t work, so I can’t activate it. Does anyone have any ideas?

As of this morning, now I can’t make calls at all. I’m getting a pop up window that says, ‘Mobile network not available.’ I hope Graphene Goat or someone else here can help.
All the others phones in my house are working, and I just put the sim card back into my old iphone (oh no!) and it’s working fine. So I know it’s the phone. :face_with_diagonal_mouth: