I do that manually; you just need to tap on airplane mode and then turn on WiFi. It's annoying that there's no option to automate this.
If this then that
Depends on carrier availability, but I believe Wifi Calling does this.
Oh, right, my carrier doesn't support that for my device yet, so I forgot about it. Does it turn the radio all the way off? I guess it would, since WiFi will just supplant all the cell radio's functions.
How does that help when WiFi is also microwave?
In the same way that a drop of poison is better than a gallon of poison.
But how do you know it's a drop and not another gallon?