Solution 1:

Google has added IPv6 support to a limited subset of regions which would enable you to run a VM with a public IPv6 /96.

Note that Google APIs and services are not reachable via IPv6.

There's a write-up of how to set it up here: GCP, basic IPv6 set up for Linux VM Instance

If you have a Google Customer Rep, you should ask them about IPv6 and GKE.

If you want to use k8s in Google with IPv6 today, you'll probably want something like Kops.

The only thing I know I need UDP+IPv6 for is DNS, and for that I'm willing to run a couple of VMs as opposed to a full k8s cluster.