That’s not inherent to IPv6 though, your ISP chose to be more specific in the location data for those addresses. If it’s sufficiently detailed as to “dox” you, maybe ask them not to do that?
On the other hand, the IPv4/v6 addresses on my A&A connection geolocate to either London or Bracknell (where their office is), about 400 miles away. I get a lot of pointless ads for things in Surrey that I have no intention of visiting.
With loose enough permissions your browser has a geolocation API that, depending on your device, will be a hell of a lot more accurate (if you have Wi-Fi hardware it can use that to work out where it is relative to the known locations of the SSIDs it can see, or straight-out use GPS).
None of this has anything to do with IPv6 - you give away some location information with your username and profile on this very site, for example.