Custom page for automatic unsubscription confirmation

Earlier this week, WP Manage Ninja shared a snippet to automatically redirect users to a custom page after unsubscribing. The issue with the official solution is that it relies on client-side redirection. The users see the unsubscription form and confirmation message flash by, potentially leading to confusion and still revealing the design deviant and uncustomizable unsubscription page. To avoid this, I wrote another snippet that handles everything server-side. Feel free to improve it if I’ve missed something.

My snippet: https://github.com/karlemilnikka/Useful-snippets/blob/main/opal_fluentcrm_unsubscription_redirect.php.

WP Manage Ninjas official snippet: https://www.facebook.com/groups/fluentcrm/posts/5701319356642021?comment_id=5701347796639177&reply_comment_id=5701364359970854.