Answer : There is no need to create add-on for this. Just need to add some code in functions.php to save consent on login into form. Read the plugin to create a consent and then save that consent in wp_gdpr_consent db table after saving the login form.
What happens when a user selects Dismiss or Decline?
When a user dismisses the notice, a cookie is created that records their selection. No further data is set for this after the popup closes. The dismiss button does not remove or delete any cookies from the user's browser.
What happens when a user selects Accept?
When a user selects accept a cookie is created, and then a record is an input into the site's database with the user's selection, consent slug, date, status (1), and IP address.