> I was aware that there are workarounds, but to me that defeats one of the core tenants of IPv6, which is that we're supposed to be doing away with this NAT and NAT-like nonsense by giving everything a globally rotatable IP.

The nice thing with IPv6 is that devices have no problem with being assigned multiple addresses on the same interface. So most of my devices actually have 5 IPv6 addresses [0]: a globally-routable DHCPv6 address (the default), a globally-routable SLAAC address, a ULA DHCPv6 address, a ULA SLAAC address, and a link-local address. So you can have a globally-routable IP and a locally-stable IP at the same time. And this is arguably a good thing, since it would be annoying to have to renumber your local network if you ever changed ISPs.

> I ran across several posts from various folks stating they could only get a /64 from Comcast no matter what they tried, so I'm not sure how universally supported DHCPv6-PD requests are.

That's annoying, and also means that you probably won't be able to get NPT to work either. FWIW, both Shaw and Telus (in Canada) will assign you a /56 via DHCPv6-PD if you request it.

[0]: I don't actually want this many addresses, but a link-local address is required for IPv6, I want my devices to have constant/easily-memorable IP addresses so I need DHCPv6, Android only supports SLAAC so I have to keep that enabled too, devices will prefer IPv4 over a v6 ULA so I need to keep the globally-routable addresses, and I want to use static addresses in my LAN so I need ULA enabled as well.