As a process of elimination can you try your sim card in another phone that's not on Android 11 @YROVI
We have seen from others that Calling Over Wi-Fi has glitched but that's usually in connection to the network needing to sometimes send an OTA configuration to reset up the service.
Calling Over Wi-Fi is driven by your sim card so your phone will only use the feature if your sim card / network push it.
Daily Driver > Samsung Galaxy s²² Ultra 256Gb in Phantom Black.
The advice I offer is my own and does not represent Samsung’s position.
I have no affiliation with Samsung.