Up on the mountain, I have 0-1 bars cellular.
If I have even 1 bar, it isn't sufficient for normal functionality; the call fails, or the call connects but the recipient can't hear me, or the call connects then fails.
However, I have great wi-fi in my house. When the iPhone switches over to VZW Wi-Fi, I can make calls all day long, with perfect reception.
But if there is even one bar cellular, the phone wants to prefer Cellular instead of Wi-Fi calling. How can I encourage the phone to prefer VZW Wi-Fi calling sooner?
Lets get this straight. Wi-Fi is a connection to the internet? The default phone app in your phone searches for cellular voice/txt with a fall back to Wi-Fi. No settings in the phone app for prefer Wi-Fi over carrier. So you would need a phone app that uses Wi-Fi instead of carrier. There is an app for that. So how is your Cellular Data (3G/4G).
Cellular Data (3G/4G): Internet
Wi-Fi: Connection to Internet via different carrier
App: Google Voice Free calls to the US/Canada