Understand the zone boundary
DNS record names managed in the zone are relative to that zone. An NS record can delegate a child name to another set of name servers, changing which party controls DNS beneath that name. If those external servers are not correctly configured, the delegated subdomain can become vulnerable to takeover.
For the same reason, the platform refuses to create an NS record rather than treating it as an ordinary address record. This is an intentional guardrail for the hosted zone. It does not mean all DNS records are unavailable; use supported record types for the service you are configuring.
Change delegation at the registrar when needed
If you intend to move the entire domain to different authoritative name servers, update the nameserver settings at the registrar. That change affects where DNS for the domain is served and should be planned before editing records in the zone. Keep a copy of required records and confirm the target provider is ready before switching.
If you only need a service to resolve to a destination, use the appropriate supported record, such as A or CNAME where valid, instead of trying to delegate with NS. After changes, allow caches to refresh according to TTL and verify the authoritative result before treating the update as complete.