How can one return to Allah Almighty and overcome the repetition of falling into sins, while feeling despair of reforming oneself within a corrupt society?

Hating sins and acts of disobedience is a sign of a living heart. True happiness is achieved by drawing closer to Allah and seeking His pleasure. "Whoever does righteousness, whether male or female, while he is a believer - We will surely cause him to live a good life." (Quran 16:97). Repeated return to sins does not harm if the repentance is sincere, for Allah is Most Forgiving, accepts repentance from His servants, and pardons evil deeds. To avoid repeating sins, strive for good companionship; they are many in mosques and lessons of knowledge. Learn religious knowledge, occupy yourself with memorizing the Quran, fill your free time with what is beneficial, frequent the houses of Allah, and strive in supplication and humility to Allah to steadfasten your heart.