2.Krishna was born in Dwapara Yuga and he died after fulfilling his Karma. There is no single instance in which Krishna appear anywhere before his birth. He is not even mentioned in Ramayana. Lord Vishnu is timeless but not Krishna. He lived his life like a human and died after getting shot by an arrow.
3.Krishna worshiped Lord Shiva. As Lord Vishnu is an avid devotee of Lord Shiva, his avatars were all worshipers of Shiva as well. Parasurama being more prominent.
4.Krishna is not mentioned in the Vedas. No single reference of him. Krishna was born after the origin of Vedas, so obviously he was not indicated in them.
5.Krishna is one of 10 Avatars of Vishnu. No one before Krishna's birth worshiped him.
6.Radha is not mentioned in any of the classical puranas except the scriptures created by the gaudiya vaishnava cult. Not even Srimad Bhagavatam contain any reference of Radha. She is a literary character originated in the Common Era.
7.Lord Kalki is the final avatar of Vishnu. Not Chaitanya Mahaprabhu. While Kalki is mentioned in the Puranas, there are no references of Chaitanya Mahaprabhu in any of the Puranas or Vedas. His teachings are anti-Vedic.
Nothing else need to be said....