Pixel 6 up to date, Google Play Services and Play Store installed. Virgin Plus (Bell Canada subsidiary) is my carrier (using a physical SIM) and I have confirmed that my plan includes WiFi Calling.

I've enabled it, and when I go to the stock phone app and dial, it says "mobile network not available". I've even set it so it tries to do WiFi calling first, no luck. I truly have no cellular service where I live, so WiFi calling woud be great to have.

I got it working. Despite my plan saying I had WiFi calling, I had to call my carrier and ask them to enable it.

GrapheneOS still doesn't ask for a 911 address to provide though.