Hello Bop,
Essay questions have to be marked manually, and students do not get a grade nor feedback until the teacher has marked their essay (https://docs.moodle.org/310/en/Essay_question_type ↗).
So the [Check] button is never displayed, regardless of the quiz settings.
I don't know if a plugin exists that would allow you to do what you want. Anyway, I wrote a question for you that does it. In fact, it is a "Short answer" question disguised as an "Essay" question. This solution is a workaround, but it works relatively well and does not require any installation.
You will find the question attached and also at https://moodleformulas.org/course/view.php?id=80§ion=2 ↗ where you can try it directly.