God manifested Himself in a physical body. He put on His earth suit. Being in an earth suit did not make Him any less God. He was God dressed up in a suit. Death is a matter of changing clothes.
We cannot know God in our human knowledge. We must know Him in our spirit.Spiritual things are the parents of earthly things. It had to have existed in the spirit realm before it can manifest in the earth.
God is not any less real because He is in a spiritual body.