Ever wondered why existence exists? Existence exists because it does. You can’t point to something that doesn’t exist to be the cause of existence. The existence of a consciousness cannot be the cause of existence because, If nothing exists then a consciousness cannot exist. A consciousness with nothing to be conscious of is a contradiction in terms.
This is why an ex-nihilo creationist god doesn’t exist for sure.
All ex-nihilo creationist theists, i.e. almost all theists, believe in the existence of a god to be the cause of existence. Existence of something can never be the cause of existence.
I would advice such theists to move the goal post by claiming creation wasn’t ex-nihilo.. Go on.. do it. We have something for you there too.