[El_RIDO]

For clients, IMHO, SLAAC is fine and means I don't have to maintain and run a DHCP service anymore. One less thing that can fail, while SLAAC only fails me if the routers IPv6 link inside the given network goes down.

Servers on the other hand, I will provision with a static IP subnet on deploy, as part of the PXE install or configuration management process, depending on the environment. They will have an ephemeral address during the install, but then query for and persist their allotted address before rebooting into the installed environment as part of their post-install.

I guess we agree that we need a single source of truth, what physical device has what IP (range) in their possession at any time. DNS is a classic way to do that, but there are other solutions, from ITIL-style CMDBs to simple config management git repos. And of course the latter doesn't mean that we don't also update DNS based on IP-assignement, DHCP is not the only tool that can be made to interface with a DNS service.