I tested this with the moodle own "Quiz" and H5P. With H5P everything is fine. You can select that the activity is completed if there is any grade. And if you fail you have completed. But with the Quiz Activity it's a different story. I have a quiz with one try. And completion by any grade. If you fail, it's not completed. Please see the screenshots attached.

Even if you select passing grade OR all attemts. It does not mark completed, if you fail the quiz and used all your attempts.