I guess one could choose between v4 or v6 but not both at the same time (dual stack). My mobile ISP also does it this way -- you either use IPv4 only on mobile data or IPv6 only with NAT64 and DNS64 to reach v4 hosts.

It's frustrating trying to work with ISPs. While there surely are business services available, as a normal customer, you're out of luck.

I count myself lucky, since I can at least get a public (dynamic) IPv4 address. The other option is DSLite with a single /64 via DHCP6. Well, I can't use that. So yeah, while it would be a fun journey trying out IPv6 - it's not feasable for me. And most likely, that holds true for others aswell.

There are options available - like the HE tunnelbroker - but those come with their own set of drawbacks.