Using new quizzes for additional practice or review doesn't allow for general feedback for essay-type questions to appear automatically. You can add the feedback generally regardless of whether the answer is correct or incorrect, however, the general feedback doesn't appear without it being graded manually.

This is a feature in classic quizzes whether the test is graded or not. There is no option for practice quizzes, graded surveys, or ungraded surveys.  General feedback is necessary when students want extra practice or review that isn't required for the course.