I need to activate One account per email address option. Since I'm using Email/Password and Google providers.

To avoid Users creating accounts from the same Email address.

I need to add a validation to check if a user is created somehow in either of the Providers in the first place and when trying to create a user with another provider I need to give an error.

To do that I found so many answers by enabling the option One account per email address, but I cannot find that option.

I'm Looking at shown screenshot page.

That Learn more link was helpful too.