Welcome @r0mantik Happy you are here
The DNS specifications of your Domain provider require that your domain name is served by at least 2 DNS servers for redundancy to ensure the reliability of the DNS setup and provide reliable DNS resolution. Meaning you need to have them like this:
ns1: ns1. mydomain. com 123.456.789 (1st ipv4)
ns2: ns2. mydomain. com 987.654.321 (2nd ipv4 purchased)
However, you can avoid all this by using cloudflare dns [TUTORIAL] How to setup DNS configurations for CyberPanel