I'm going to move on to different arguments. If God is Necessary then he exists true, and so it seems like cheating to just assert he is necessary. I get it.
The derivation of why God must be necessary has been proven many ways and in fact, even it wasn't, and God can be grasped to be necessary the following can be phrased:
(1) If God can be grasped to be necessary, then it will be known to exist by the one grasping God is necessary.
(2) God can be grasped to be necessary.
Therefore God exists (the conclusion is more, but that can be derived from conclusion).
To prove God can be grasped to be necessary is easy.
Absolute life (mathematically) cannot miss anything in life. This proves nothing is on par and equal with it in eternality, there is no divisions, parts, etc, but it also shows all creation derives existence from it, and is dependent on it (borrows existence without God losing any).
Now God is defined to be greatest being. Let's think of wisdom. Suppose God lacked a tiny bit of wisdom. He would cease to be God. It's the same with life, power, love, etc.
Therefore if it's possible any independent existence exists, it's impossible for God to exist.
Another way to think of it, suppose the absolute being exists. Then suppose another one that doesn't know about that one exists. It's a contradiction, because they both are not all knowing anymore and also both not absolute in life. Just as impossible for there to be more then one God if God exists, then it's impossible for any independent existence to be possible and God being possible. You have to choose one.
Another way to phrase, suppose God exists, and then it's possible other absolute beings on par with him exist but don't exist in actuality. The contradiction is the same if two Gods exist in actuality as it is for a god to exist in possibility. And since if God is possible then he is necessary, it will follow that if he is possible, he exists. So like I said the disputable premise is whether or not God is possible.