Server, VPS and Name Server

I have to transfer some domains to a new server and I want to resolve their name with my own Name Server.
So, I bought online a dedicated server to install the domains; a VPS to be configured as Name Server and which I named “ns1”; a new domain “domain-ns.tld” to point to “ns1.domain-ns.tld” by creating a new A record pointing to the IP address of the VPS.
Later I will configure the domains I already own to use this new Name Server.

I already have Bind9 and Webmin installed on the VPS.
I was starting the first configuration when I had a doubt: if I let BIND resolve itself, I will lose the original configuration currently present in the domain panel, where I created the A record.

Am I doing something wrong?

=* Update
I created a GLUE record with the name ns1 and entering the source DNS IP.
When configuring BIND do I always use the IP address of the VPS or the one in the GLUE?

SYSTEM INFORMATION
OS type and version Debian 12
Webmin version 2.105