How can a committed young man rid himself of the devil's whispers that drive him to commit acts disliked by Allah when alone, despite his diligence in acts of worship such as praying in the mosque and reciting the Quran?

You must persevere in reciting the Quran, lowering your gaze, and staying away from sins. Repel the whispers of Satan by increasing supplication, seeking Allah's help, and relying on Him, as Allah Almighty says: (Indeed, he has no authority over those who believe and rely upon their Lord). Allah has confined Satan's plot to mere whispering. Increase your remembrance of Allah Almighty so that hearts may find tranquility, and occupy yourself with beneficial deeds, beware of idleness which enables Satan to enter your heart.