Hi, Have you checked after the update if the Wi-Fi calling option was somehow reset after the update?
Phone app > Settings > Wi-Fi Calling.
If it is already set to Wi-Fi preferred, then try the following:
Switch the option to Mobile network preferred. Turn the SIM switch off and on again. Restart your phone. Now reverse (switch to Wi-Fi preferred) and toggle the SIM switch off and on and restart your phone.
Check if the above helps.