Big Tech will never fully support IPv6 - IPv4 forces consumers to use centralized services.

I recommend IPv6 mesh VPNs like Cjdns, Yggdrasil, Pinecone.  Every device gets a permanent cryptographically authenticated IPv6 that is also mobile.   A SIP client can use the raw IP in the contact list - no need for telco, DNS, or TLS.

Where IPv6 is supported, the mobile IPv6 protocol (easily self hosted) lets an IPv6 on your net be anywhere that support clearnet (normie) IPv6.