You are correct, @mfeeney2. The options for what to show students after they complete a quiz that are detailed in the Canvas Guides documentHow do I restrict students from viewing quiz results in New Quizzes? do not include the option to show the results only once. Accordingly, that option is not currently listed on the New Quizzes Feature Comparison, though perhaps it will be included in a future release.
However, I wonder how only seeing the results once fails to prevent your exam questions and answers from being compromised. Here's what I would do instead: Hide results from students until after the exam due date has passed and then change the settings and/or use some class time to review the answers to the questions. That way you would save having to meet each of your 65 students individually and also mitigate the risk of unauthorized cooperation among them.
I’m going to mark my response as a solution, but there can be more than one. I hope our colleagues here in the Community can share other options for meeting the interests you describe.