In my case, it's carrier. I have Samsung Galaxy A16, and it supports "wifi calling". But, my carrier Freedom Mobile doesn't. I don't even
see "wifi calling" entry in the Settings.
Sample size of one. I have a Pixel 9 and freedom is my provider. I do have a setting for Wi-Fi calling though I haven't enabled it. I'll give it a try tomorrow in a location that I know has Wi-Fi but not good cell coverage by Freedom
If your phone doesn't even have a switch in the settings, then how can you be sure that Wi-Fi calling is supported on that particular model (and national variant)?
I'd suggest both phone and carrier need to enable it.
- Evan