??? The location and the file name of the certificates don’t change, so why would I have to do that?

On the contrary, before I disabled the certbot’s Nginx integration, every three months certbot would “manage” to break my Nginx and I had to manually repair it.

I think we are not talking about the same thing. I mean the Certbot extension that automatically modifies the Nginx config files. A telltale sign are usually the comments "#managed by certbot” that it likes to leave behind all over your config files.