If you delay prayers out of laziness, do you have to do the Shahadatayn all over again, take Ghusl and start performing Islamic rituals or just seek forgiveness from Almighty Allah and never delay the prayers again.

Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

Delaying prayers from their fixed times due to laziness alone is not considered Kufr that drives one out of Muslim community. One is not required to renew his Islam for this act. This is the correct opinion of Muslim scholars, even though delaying prayers from their fixed time is a great sin.
Therefore, you must repent from that sin, ask forgiveness of Allah, keep performing prayers at their fixed times and do voluntary good deeds as much as possible.
May Allah bless you and us and guide us all to what is beloved to Him.
Allah knows best.