What is the way to avoid cheating in a school where the administration encourages it, knowing that I am a high-achieving student?

You must denounce evil to the best of your ability, for the Prophet, peace and blessings be upon him, said: "Whoever among you sees an evil, let him change it with his hand; if he cannot, then with his tongue; if he cannot, then with his heart—and that is the weakest of faith." If you do what is incumbent upon you, then those who go astray will not harm you if you are guided, as Allah Almighty said: "O you who have believed, upon you is [the responsibility of] yourselves. Those who have gone astray will not harm you when you have been guided."

Part of denouncing this is to explain to teachers and students the prohibition of cheating in exams, for it is a grave sin and a serious offense due to the widespread harm it causes. The Prophet, peace and blessings be upon him, forbade it, saying: "Whoever cheats us is not of us." And explain to the administration that allowing cheating in exams and overlooking it by teachers and invigilators is one of the great calamities. If there is a higher authority than the direct administration, then explain it to them so that they may hold those responsible for negligence accountable and stop and prevent such cheating.