I’m sorry, but to me it isn’t nearly that complicated.
In Genesis Chapter 5 we learn all we need to about Who and What God is and Who and what man is to Him:
1 This is the book of the generations of Adam. In the day that God created man, in the likeness of God made he him;
2 Male and female created he them; and blessed them, and called their name Adam, in the day when they were created.
3 And Adam lived an hundred and thirty years, and begat a son in his own likeness, after his image; and called his name Seth:
God/Adam
In the day that God created man, in the likeness of God made he him;
Adam/Seth
and begat a son in his own likeness, after his image;
We are like God just as Seth is like Adam. I don’t know how it could be more clear.
The "likeness" is the spiritual aspect. None of us have seen God and none of us know what He looks like so none of us can say that we are the physical "likeness" of God. However, we do know that God is a spirit and we were created with a spirit.
Our "likeness" to God is our spiritual aspect, not the physical aspect.
There is a flaw in your logic.
1) We are from Seth/Cain (actually Noah). Therefore we are like Adam-not God.
2) Adam sinned. God does not. Therefore Adam is not like God.
3) Since we are from Adam, and Adam is not like God, we are not like God.