How can a person grasp God's wisdom in the decrees of their birth and the circumstances of their life so as to feel content, especially if they wished for better circumstances and are not resigned to what is predetermined?

Everything that happens in the universe is by Allah's decree and destiny, and there is wisdom in it. Belief in destiny and contentment with it is obligatory for the servant. It is legislated for the Muslim to strive to change his condition through legitimate means such as supplication (du'a), thanking Allah, refraining from sins, frequently seeking forgiveness, and looking at those who are less fortunate in gratitude to Allah for His blessings.