Solution to what? If there isn’t a solution, mention why and leave it is
Again agreed assuming you can do this configuring wireguard or openvpn on your router with VoWiFi, VoLTE forget that type of config.
As we said, Both Android and iOS (for the most part) deliberately does not route VoLTE or WiFi over a VPN tunnel and you kept trying to provide a solution almost non-existent (almsot because again only good point is like the Tor you mentioned and VoWiFi solution if even possible to do at this point