Dark matter is merely a placeholder, the same as X or Y in algebra, for something we don't understand. Just because we don't understand it does not mean we never will, and it does not mean that "the universe is trying to show an existence of a god." Such thinking was common a long time ago used by religions to show the existence of a god. We didn't understand quantum mechanics or know about quarks 100 years ago, does this mean in 100 years if we do fully understand dark matter can we say it doesn't prove god again? The ancient Greeks did not understand the sun rising or setting, and attributed it to Apollo riding his chariot across the sky.
With that being said, we still know a lot about dark mater, such as it is about 23% of the universe (note that we can get a pretty good measure of dark matter by measuring the effects of gravity on things we can see) and that it is web-like, interwoven with regular, visible matter.
We don't understand many things, this does not mean there is proof of a god, and we still understand some things surrounding dark matter.
Now for a more personal side, as opposed to scientific, your "theory" is backed up only by faith that there is an all powerful creator, not by fact or logic. Also, if the universe/ god wanted to show the existence of god, wouldn't you think there would be an easier approach than that?