How you approach it depends on how you show the questions, what data you have available in which context and if you maintain the order of questions.
If you have the boolean isLastQuestion, you should set this value when finalizing a Quiz. This is either when you commit the Quiz and Questions, or when you open this page. Then you can show the button with conditional visibility based on that attribute.
If you can share a screenshot of the page in Studio Pro as well, we can see what data is in which context.