How can one get rid of masturbation and its psychological consequences, and does Allah forgive sins related to it after repentance, and does it affect success and achievement in life?

You must continue to repent of this sin and not despair, for the one who repents of a sin is like one who has no sin, and you will not be punished for it after your repentance. What helps you abandon it are frequent fasting, constant remembrance (dhikr) and supplication (du'a), keeping company with the righteous, avoiding temptations, and occupying yourself with what benefits you. If you do not repent of it, then there is a fear that Allah Almighty may punish you.