> but every IPv6 setup that I've seen still gives every device a unique globally-routable IPv6 address, with no NAT at all.
Mine all have link-local addresses (I do have a real static IPv6 address block from my ISP, at great expense…) - so I’m not sure what I did wrong in my Ubiquiti gear.
A link-local address is required with IPv6, so your devices probably just have that in addition to a globally-routable IPv6 address. This isn't a problem though, since devices have no problem having lots of different addresses on the same interface [0].
[0]: https://news.ycombinator.com/item?id=44773981