User registration – own WP site vs. standard WP login site (redirection)?

I want to secure that only logged in users can comment on posts.
As a result, potential commentors obviously need to be able to go somewhere to login (or register) first.

This option is ovbiously already “included”:

OnPaste.20181004-183738

However, if potential commentors click this link, they’re taken to the standard WP login (or registration) page:

OnPaste.20181004-183833

Is it not possible to secure that the redirection takes potential users to your won customized login/registration page?

Thanks in advance for any help!!!

The page I need help with: [log in to see the link]