Registering own NS for a domain is not mandatory. For example CloudFlare can handle the DNS zone for the domain. CyberPanel comes with automatic DNS synchronization with CloudFlare. That way the CF DNS zone can be managed directly from CF. That can be done for a single website or for CF as a whole. The latter will synchronize every newly added domain in CP with CF. In order to synchronize the two instance, the CF API needs to be added in CP.