If you live somewhere with terrible cell phone reception, what do you use for making phone calls?

We live in a suburb with notoriously bad service, but my end of this street is just a dead zone. If we use WiFi calling on our cells phones, it’s ok, though we still have dead zones within the house.

I want a land line since even with WiFi calling it can be iffy, but DH and some others have said it’s all the same since “landlines” just go through the cable/ internet anyway. As I understand none will work in a power outage? Does anyone know more about landlines? Also going through Comcast vs something like Vonage (which would be much cheaper)? I’m so fed up with dropping calls.