Of course, it should be readily apparent that there is a significant difference between saying that a god exists and demonstrating that claim to be true. It should also be readily apparent that not all possible gods are ones which are capable of creating universes. So, you still have many things to prove. On this point, you have gotten off track. I'm merely showing the insufficiency of your simplistic argument.
Theism covers an awful lot of possibilities.
At some point, you're going to have to start getting specific or you have a meaningless statement. This simplistic answer does not provide any support for the actual existence of any such entities nor of their powers. I can't believe that somebody who claims to be educated could even ask such a question. Polytheism is much older than monotheism and also predominates among all forms of religion. Since Man's different religions have many different and mutually-exclusive stories about various gods which may or may not have created the universe, any claims in favor of an intelligent designer are necessarily going to run up against this problem.