OK, I'm a bit new to DNS, but I'm having some trouble finding the answer to this. I have a domain registered at google domains. As with other registrars, you have access to their free DNS, and although I realize you can change these, I also noticed the option of entering "NS" records (as opposed to other types, e.g. A, CNAME, etc.) for individual subdomains (zones?)--even for the bare domain (e.g. example.com). How does this differ from the registrar's nameservers? Will entering NS records for a bare domain conflict with the registrar's nameservers if you haven't changed them? Or do the NS record ones take priority over the registrar ones? Could someone explain this to me?
Also, if I wanted to use cloudflare for one subdomain only, could I just enter cloudflare's dns servers as multiple NS records for that subdomain, or would I have to change the main DNS servers (away from google, that is.)? Thanks very much.
Follow up:
I just did a dig example.com any
and noticed that the registrar's nameservers show as NS records for the bare domain. I thought that the registrar's DNS server settings were somehow separate from the ordinary resource records (A, CNAME, etc.). I guess I was wrong.