Your unbelief that there is God is a form of belief or religion
It's not. NOT believing something is by definition not a belief.
A belief is to accept something as true. The belief concerning god(s) is theism. Atheism is the opposite.
because you believe it to be TRUE that there is no God at all, that's your main argument.
No, it isn't. I have factually never made that argument. Nore is it what atheism is.
Just like I said in the post you are replying to: it seems you don't comprehend the difference between "I don't believe X" and "I believe X is false". These are two different things.
Have you ever heard the gumball machine analogy?
It goes like this:
There's a giant gumball machine with an unknown amount of gumballs in it. You can't open it up to count them. Then some guy comes up and claims that there is an even amount of gumballs in it and asks you if you believe him (which is to say, that you accept that claim as being true).
You answer "no, I don't accept that as being true". You don't have enough information to commit to that position. So you can't accept it as being correct.
Does that mean that you will answer "yes" to the question if you believe there is an odd number in there? Off course not.
The claim "there's an even number" is the equivalent of "a god exists" in this analogy.
Concerning the existence of god, you can make 2
distinct claims:
1. god exists
2. god does not exist.
Atheism is a position on the
first claim. The claim that a god exists. The second claim isn't even addressed, nore made.
We can go further into the courtroom analogy.
A defendant is either guilty or innocent.
But in a courtroom ONLY the claim of guilt is addressed.
This is why a judge will rule either guilty or not guilty.
So atheism is like saying that you judge god "not guilty of existing". That doesn't mean that you judge him as not existing (or "innocent of existing").
The claim being addressed is "god exists". Not "god does not exist".
You should really learn the difference between:
1. I don't believe X is true
and
2. I believe X is false.
They are not the same thing.