I am using the galaxy S20 Indian version and on the jio network I live in Andhra Pradesh Vijayawada.
I have to say voice over wifi is working seamlessly on my new S20 on the jio network, and it's very helpful at my home which has a little bit disturbance in the signal especially after buying the S20 which has lower potential receiving the signal as compared to the note 10 plus which was my previous phone but anyways, it's a very good feature, voice clarity and call quality is far better than a normal call, the only setback is that call recording feature is not available when you call someone on Vowifi, I think Samsung will change it in the next coming update, let's see.
The bottom line is that it's very useful feature and as everyone has got Wi-Fi at their office, house ,malls, cafeterias, restaurants and hotels these days, it's a functional and a must have feature for every smartphone.
