> Unlike IPv4, my LAN addresses include the prefix, so every time they change it, all my LAN addresses change.
Yes, a topic of active discussion at the IETF. See perhaps BCP RFC 9096, "Improving the Reaction of Customer Edge Routers to IPv6 Renumbering Events":
* https://datatracker.ietf.org/doc/html/rfc9096
And informational RFC 8978, "Reaction of IPv6 Stateless Address Autoconfiguration (SLAAC) to Flash-Renumbering Events":
* https://datatracker.ietf.org/doc/html/rfc8978
A few drafts, like "Improving the Robustness of Stateless Address Autoconfiguration (SLAAC) to Flash Renumbering Events":
* https://datatracker.ietf.org/doc/html/draft-ietf-6man-slaac-...
Using ULA seems to be what a lot of folks recommend: