Another AJAX CSRF question
Thanks to Robin Schambach. The answer was as simple as serialize the form data with the CSRF in there already by using the default {{ getCsrfInput() }}


  serializeArray won't produce data in a way Craft CMS will proceed it.
  It's not a good idea to do that. Besides that why don't you include
  the token in your form from the beginning? Because this is never the
  default code you can find in every ajax request – Robin Schambach 14
  hours ago