I’m writing about your name server requirements page:

https://www.norid.no/en/om-domenenavn/regelverk-for-no/vedlegg-f/

I think that requirement 4:

Accessible name servers 

Name servers must be permanently connected to the Internet, and must have a permanently assigned (fixed) IPv4 address. The name servers may also have an IPv6 address, and this too must be permanently assigned as required for the IPv4 address. The name servers must be connected to a stable and reliable infrastructure.

is somewhat out of date relevant to current best internet practices…

At the very least, IPv6 should no longer be options.

Ideally, IPv4 should be optional.