As per your concern, we want to inform you that the VoNR (Voice Over 5G) feature is supported by your device, as of now it is only working with Jio Network, and Airtel / VI has not been implemented yet.
Kindly enable the setting by the below path: Settings > Connection > Mobile Network > VoNR (Voice Over 5G)
Note: By default, this option will be off, so you have to on it manually. however, if still can't use kindly contact the network operator once, to make sure there is no issue from their end.
