AFAIK in Germany for DOCSIS it's common to have DS-Lite in the mode with lightweight 4over6, so the CPE does the NAT and the carrier just range checks the client side IPv4 port to fall within that customer's block.

No state at the carrier; IP:6 native network.

If you buy a full IPv4 you get one for yourself but I expect still through the same tunneling machinery to keep the network IPv6-only.