Today I learned how to use socat to pipe IPv4 traffic to my #homelab that's accessible only over IPv6 (thanks 1&1 and DS-Lite).
Set the DNS A record to a VPS I already have, spin up a reverse proxy on the VPS via docker, point the right domains to a socat docker container which TCP6's the IPv4 traffic the right way. Don't forget to add an IPv6 network to the socat container. Done.