The perfect Law of God is universal.
It is based on love and benefits every created being since it precludes any action that would harm another person.
God has a family and a set of house rules.
The first human couple decided they could decide for themselves what good and bad was what right and wrong was. They left the family, however God is love and provided for them anyway.
However, the couple would have to live outside of the family without the benefit of eternal life. They would be imperfect.
God withdrew his spirit from them and they became sensual beings with two sets of nerves that enabled them to have love but not fully. Holy spirit, the life force of God would not be present to keep them alive forever or give them his qualities.
Their bodies would break down eventually, grow old and die.
God knew that some of their children would appreciate eternal life and want to be part of the family and accept God’s way of life based on love. He had made no mistake creating humans.
He knew because he had faithful children in Heaven, in particular, his first created Son who had proven his love for his Father for eons.
It would work out eventually.
The problem is that God cannot die. He is eternal. He has a perfect memory but cannot remember a beginning. Therefore he has always existed. If he has always existed then he always will exist. It is logical.
He used a provision of his law that if the sin was atoned for, life for life , then life could continue. God cannot die, he is eternal, so he could not provide the sacrifice himself.
He would have died for us if it were possible.
His first created Son, Yehohshua, willingly offered himself as the needed sacrifice and God transferred his life force to the Earth.
He would be born a perfect human and eventually die a sacrificial death.