Split .npmrc registry settings and authentication

Currently, authentication data is stored in the .npmrc

I want the registry and always-auth part to be in version control but not the authentication.
I want the authentication to be in a git-ignoreable file.

I don’t want the authentication global/user-specific.

I understand that this would not be a problem if you have a CI/CD workflow where a server publishes the package but we don’t have this at the moment.

Maybe there’s already a way to do this that someone could point me to?