How can one deal with the spiritual illness of lethargy in worship and the return to watching pornography and masturbating, especially after and during Ramadan, and what is the correct way to repent in order to return to Allah?

The questioner must repent to Allah from browsing the satanic websites that led him to neglect prayer, masturbate, violate the sanctity of Ramadan, and listen to music. Some of these sins are major sins. It is not permissible to abandon prayer or neglect congregational prayer due to falling into sins, and one must beware of despairing of Allah's mercy, for sincere repentance erases all sins.