Any way to enable VoWifi in MIUI Chinese ROM?

[xymeng]

I bought a Chinese version Xiaomi 12x recently and was trying to enable the VoWifi. I've tried to use *#*#869434#*#* and succeed to see the VoWifi option in the settings. But after I enabled it, nothing happens. Is there any way to enable it in Chinese version ROM? I have set this phone up with my needed APPs and data so I really do not want to flash it and set it again Or is it possible to enable VoWifi by flashing MIUI EU or Global?

Thanks!