The protagonist is a system, not a person, but he becomes a person.
The diaosi got the system and became a winner in life. The goddess who was seduced and abandoned by the diaosi was just his stepping stone. When the goddess was betrayed and committed suicide in heartbreak, the system realized that she was the person it had let down.
After the rebirth, the system tried every means to prevent the success of the diaosi and the seduction of the goddess, and seduced the goddess himself.
In fact, it's the kind of thing where the stallion writes and then the system is reborn to prevent the diaosi from succeeding and seducing the goddess.