Is it necessary to make up the prayers and fasts after bleeding occurred following ghusl from menstruation due to ignorance and not performing ghusl again, along with not remembering the number of missed prayers?

If the blood that returned was at a time when it could be menstruation, then it is menstruation. You must make up for the fasts of the days you saw the blood, and make up for the prayers you performed after purity was attained and before ghusl, according to the majority of scholars, due to their invalidity. The most cautious approach is to make them up. If you do not know their number, then exert your best judgment and make up what you believe, most likely, discharges your responsibility. However, if it is considered irregular bleeding (istihada), then your prayers and fasts are valid, and you owe nothing.