PiHole is actually pretty great for this. I set up some firewall rules in OpnSense to force all devices to use PiHole as a DNS server. Then log all queries.

You can see which clients are using ipv6 and how many queries there are. I would estimate that about 60% of iPhone traffic in my household (by far the busiest devices) is ipv6. We usually use big sites though like Reddit, twitter, google, etc.

And then there’s the Rokus that don’t support ipv6 at all. Considering how cheap they were it doesn’t really surprise me.