How can one get rid of the habit of masturbation that began at a very early age and continued for many years, leading to feelings of guilt, self-loathing, and fear of God?

Masturbation is forbidden (haram), and it is obligatory to avoid it and to repent sincerely from it by stopping it, regretting having done it, and resolving not to return to it. Do not surrender to the despair that Satan inspires, making you think you will not be able to quit it. Rather, hasten to repent and do not preoccupy yourself with what tomorrow might bring, for a sound repentance erases what came before it. Seek refuge in Allah with sincerity, acknowledging your weakness, so that He may help you repent and remove the love of disobedience from your heart. Be keen on lowering your gaze, closing the doors to temptation, strengthening your connection with Allah, and occupying your free time with beneficial activities.