This google metric measures adoption in access networks, but at this point I feel more interesting metric is adoption in services.

One such stat is here:

> adoption ranging from 71% among the top 100 to 32% in the long tail

https://commoncrawl.org/blog/ipv6-adoption-across-the-top-10...

Getting full coverage on AWS (/GCP/Azure) and few other key services (GitHub...) would be significant here imho.