Is what is happening—people's mockery, contempt, lack of success in marriage and work, and instability therein—due to practicing masturbation for 11 years before repentance?

We ask Allah to keep you steadfast in repentance. If you repent to Allah, it is hoped that He will accept your repentance, for He says: "And it is He who accepts repentance from His servants and pardons sins." What you complain of may be due to your shortcomings, for He says: "And whatever strikes you of disaster - it is because of what your hands have earned," and the Prophet (peace and blessings be upon him) said: "Indeed, a servant is deprived of provision due to a sin he commits." You must take the necessary means and strive to achieve your goals.