I simply didn't do the research. My two previous Sony phones  came from the Wind/Freedom store, but for the last one they didn't have any Sonys in stock so I bought online from Mi4Canada (the phone shipped from Asia).

The latest, Xperia 10 IV (2022), supports Wifi calling in general but mine has neither of the settings (Settings or Phone->Settings). I took it into the nearest kiosk to have it confirmed. Some searching told me that this was a function of Sony withdrawing from the North American phone market.

To check, I put the SIM card in my previous Sony (Xperia XA1 Ultra), enabled the settings which were present, and it worked. So yes, Freedom supports Wifi calling but this Sony doesn't. Since it's about to become my backup phone, maybe I'll try installing a non-Sony Android.

Mike