This used to be an area of interest for me. I think no argument is good enough either way. Either you believe that God is in control or you don't. You have no control over whether the trinity is true or false and over whether people believe it or do not. You can think you do and that you can prove things. I don't think it works that way.
In answer to your question there is the plan of attack: open to the gospel of
John chapter 1 which we can read like its a commentary on
Genesis 1. First of all assume it is not a trinitarian book if you like.
There are non-trinitarian Christian ideas about this that are mystical. For example when Jesus is quoted to say "Before Abraham was I am" some like me take it to mean that Jesus is preeminent, not that he exists before Abraham but that he is calling himself the goal of or purpose for Abraham.
Goodness sakes how can a person be a Christian and not know the difference between preexistent and preeminent!
I'm kiddin. I'm joking about myself and my arrogance. Jesus is not preexistent! No, he is preeminent which is completely different!
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It turns out that proofs about the trinity are complicated as are proofs against it. You look up one verse and its like "No there isn't a trinity" but then look up another verse and its like "Maybe there is a trinity." That makes it difficult to have a discussion let alone an argument. I've seen arguments about it on the internet for over 23 years. In my opinion such heated disagreement and pity for the other side cannot be the will of God.