God didn’t change He always had a plan from the beginning to redeem us - buy us back from the devil. That plan had to await for just the right time. In the meantime God had to ensure a remnant was preserved and not utterly destroyed by Satan, or all would have been lost. It’s the reason for the flood, Joseph and the saving of Gods people from starvation, Moses saving people from the Egyptians, capture and being taken away to Babylon, all those battles and indeed the whole Old Testament history!
Adam and Eve literally sold themselves to Satan he became their master and they became his slaves.
For those that are redeemed we are now under the authority of God and are no longer slaves to sin.
Try a word bible study about kinsman redeemer. It’s fascinating and woven all through the Old Testament. Jesus is the ultimate kinsman redeemer He paid an awful price to buy us back.
It was human beings who mucked up everything and satan who deceived them. The world forever after was changed the penalty death. Jesus bought us back by paying the penalty.
Romans 5:6-8 NKJV
[6] For when we were still without strength, in due time Christ died for the ungodly. [7] For scarcely for a righteous man will one die; yet perhaps for a good man someone would even dare to die. [8] But God demonstrates His own love toward us, in that while we were still sinners, Christ died for us.
Romans 6:21-23 NLT
[21] And what was the result? You are now ashamed of the things you used to do, things that end in eternal doom. [22] But now you are free from the power of sin and have become slaves of God. Now you do those things that lead to holiness and result in eternal life. [23] For the wages of sin is death, but the free gift of God is eternal life through Christ Jesus our Lord.
Galatians 4:4-7 NLT
[4] But when the right time came, God sent his Son, born of a woman, subject to the law. [5] God sent him to buy freedom for us who were slaves to the law, so that he could adopt us as his very own children. [6] And because we are his children, God has sent the Spirit of his Son into our hearts, prompting us to call out, "Abba, Father." [7] Now you are no longer a slave but God's own child. And since you are his child, God has made you his heir.