Hi Mariusz,
This can be done only with custom CSS code. Please paste the following CSS code in Appearance -> Customize -> Custom CSS.
.qsm-submit-btn{
display: none !important;
}
Please do tell me whether the above code worked or not. In case, it doesn’t work then please share the quizz’s URL with me so that I can help you with the required code.
Kind regards,
Kriti