The Lord Jesus Christ did not say that Peter is the rock on which He will build His church. He said, “Thou Art Peter, and upon this rock I will build my church.” (Matthew 16:18)
Peter himself understood what that rock was. That rock was the Spirit of Obedience.
The real issue here is the issue of salvation. Even if you declare one million times that Peter is the rock upon which the church was built, it would not affect the serpent seed in any way. It would not address the issue of salvation because the serpent seed is still there. You can declare that confession one million times but it will still, in no way, solve the serpent seed problem, which is the issue of sin, which is what salvation is all about. It is not about what church was erected by Jesus Christ.