The question above for the most part, been reading up on it. Also want to it for learning purposes.
And can be identified/tracked individually by outside entities. In IPv4, a website sees both my device and my kid’s device as the same IP. In IPv6 they’re different so this just provides more ways for them to track you.
That’s the reason for rcf 4941. It randomises the host part of your IPv6 address.
First of all they use much more than the device IP to identify individual devices. IPv4 is no longer all that useful for identification with things like CGNAT being common.
But with IPv6 they’ll see my device IP, then they’ll see the same device with completely different IP, then again. Same for my kid’s device. But again, all of the above applies. It is a concern, but there are much better ways of tracking you anyways.