Oh Hallelujah! Adding to what you shared especially when you talked about God adapting to man in order for him to fulfill his purpose. Yes, God’s change of mind in his dealings with man doesn’t contradict who he is- his essential character from whence we can say that he is unchanging.
The ways of man are like shifting shadows. The strength of man outside God can fail. And so God takes the position of one who wants to relate. However, this would be on his plane and through the sacrifice of Jesus, he got down to our plane( the God who cannot behold iniquity). He took upon himself the sins of men for the purpose of making man his friend. And now, instead of death being the wages of sin… God’s judgment becomes forgiveness and the revelation of his unchanging nature (love) to that man ( who was a terrible sinner) who has now repented and has put faith in Jesus.
This is all about being able to still relate with the changing man yet being unchanging in his nature.