Genesis does not say "Man has become like us gods".
Then the Lord God said, ‘See, the man has become like one of us, knowing good and evil; and now, he might reach out his hand and take also from the tree of life, and eat, and live for ever’
So where does it say, "Man has become like us gods", as in gods (plural)?
It's the notion and sentiment that counts. One can say the same thing in various ways and they will all mean the same thing.
God is speaking and says like one of us. That speaks for itself.
So if I say, "We sat and watched the news this evening, I am claiming that there was more than one Alan Co********* in our lounge this evening"?
Are you not aware of the use of the plural in Hebrew to denote majesty (not unlike the Queen saying, "We are not amused")? Heck, elohim is plural, yet is used in places in the OT where God is clearly one rather than plural. Even that were not so (which it is), why would it not be God (singular) speaking to the angels? Why do think that God is speaking to other gods when that happens nowhere else in the OT. Bear in mind that the text of Genesis 1-3 is not the oldest in the OT so it is not an indication of a change from polytheism.
The Queen is referring to her court, who are all humans and of her 'clan'.
If what you say is right then why did the translators not adjust it to suit. It clearly says 'God said' and It uses the term 'we'. If it is obvious that only one person is talking then why wasn't the 'we' been replaced by 'I'? Or if the Hebrew word for God is plural then why doesn't it say "the Gods said". (so what you are saying about the Hebrew is that when it says God anywhere in the Bible it actually means "the Gods"?)
Why do think that God is speaking to other gods when that happens nowhere else in the OT.
But it does in Gen 11:7 (well in the NIV) - "Come, let us go down and confuse their language so they will not understand each other." If God, singular, is so powerful why would It need anyone else to help with this task, say like the angels?
Elohim is a plural word, yet when it is used to speak of God the verb form it takes is singular. A literal rendering would be "Gods is great". This demonstrates that, at least with the word
elohim where it refers to God, a plural is used to depict a singular being. This bit is not controversial.
As for the "we" bits we have been discussing, this seems to be something similar, as I say not unlike the Queen (allegedly) saying, "We are not amused?" I am giving an analogy there and analogies do not prove anything, though they may illustrate something. The use of "we" and "us" by God in Genesis is not proof of him speaking of there being gods/Gods plural. That is all.
As for how it is translated, sometimes it is not possible to translate something into another language without a fairly long explanation.