I was grading an online exam yesterday. You're lucky.
This program used an SPA.
The core workflow is hidden and split over multiple "tabs". Tabs include: question, given answer, score awarded. That's right, none of those are available simultaneously. Yes, 70% of its window goes unused when full-screen.
Going through all students can be done in (at least) two ways. In the first, you can press a button to proceed to the next student, but you cannot go back a student. In the other, you click "save" after grading each answer. This returns you to the overview of students.
The overview displays 20 students per 'page' (tiny font, tiny rows), irrespective of your window size. There is no "next student" button, you have to click the student you want to grade. If you're grading past the first page (e.g., student #21): surprise! You're back on page 1. Clicking the student's tiny row requires more precision than you'll need the rest of your work week on modern desktops.
I could go on. I will, actually. Apparently, standard workflow is you can never go back to an already graded answer and points awarded become final; I accidentally used a workflow that didn't have this idiocy).
In short, there is no way this product's core functionality was tested. Any tester would have exclaimed "are you kidding me?!", and have walked out. Or inflict physical violence on their computer. Or whoever hired them.
In short: setting this product on fire is the best reason for bringing back floppies in 25 years.