It’s easy enough to prevent cheating on multiple choice exams. I wrote my own test questions. I used to make 4 versions of each test, each one with the same questions but each having a different starting point. No student had another student with the same exam in front of him or on either side. So there was no one to copy answers from. As far as they could tell the exams were randomly distributed. Anyone who did copy answers from a neighbor’s scantron sheet would get 80% of the questions wrong.
The class after the exam we would go over them to analyze why the right answers were right and the wrong ones were wrong. I then collected all exam questions and answers. Over several decades the average scores on the exams hardly changed, and it was virtually always the case that the good students did well and the poor students, especially those with spotty attendance, did poorly.