Is the failure to achieve desired results in exams, despite diligence, hard work, and prayer, considered a punishment, a trial, or divine decree and destiny, and what should be done thereafter?

Everything that occurs in the universe is by Allah's divine decree and destiny, and the servant must be content with that. Allah Almighty says: "Indeed, We created all things in due measure." (Quran 54:49) What befalls a Muslim may be a trial and a test. Therefore, a Muslim must fear Allah, strive diligently in their studies, supplicate frequently, and do good deeds, leaving the outcome to Allah Almighty. In all circumstances, there is good for the believer, as the Prophet (peace and blessings be upon him) said: "Wondrous is the affair of the believer, for there is good in every matter of his. If he is afflicted with ease, he is grateful, and if he is afflicted with hardship, he is patient. Thus, it is good for him."