This is why I pay attention to word meanings.
Meaning of Great
quote:
And the proof;
X + Y > X
Greater than means larger than.
quote:
God as one of his essential attributes is to be greater than anything else.
Do you really mean one of his attributes is to be larger than anything else?
God is the largest thing imaginable?
Nothing can exist that is larger than God?
I think your proof went poof.
Great is a word that can mean size depending on how it is used and it does refer to size in the Bible, but it also refers to power and authority.
God + Creation doesn't make a new entity that is larger in size or more powerful than God.