@freemo @cr well, qoto doesn't have IPv6 at all. Normal DNS has only an A record for qoto.org (no AAAA).

However, I use DNS64, so get back a synthetic NAT64 AAAA address (starting with 64:...). A "not proper" IPv6 address.

To add IPv6 you either need a hoster that provides it, or put a CDN in front (although as has been pointed out to me that means you need to also trust your CDN as well as your hoster, e.g. for HTTPS security).