Why would you assume that it must make sense to you? That you should be able to understand it?
We are a species very curious about our world. It's in our genes to assume we can make sense of things and indeed we constantly try to do so.
The origin and purpose of existence is a complete mystery to all humans.
It seems to me that the evidence is very clear ─ the universe exists because of the operations of cause and effect within physics. Nothing suggests it's constructed for a purpose, and nothing suggests that purposes are found anywhere but in the brains of relatively advanced living creatures. Nothing suggests that life began on earth for a purpose, and nothing suggests that humans have been directed by any overarching external intelligence to become what we've become.
Yet not knowing doesn't mean that there is no origin, or purpose.
There's evidence for the Big Bang, which offers two principal possibilities ─ that the matter and energy of our universe pre-existed the universe, OR that the matter and energy of the universe came into existence out of absolutely nothing ─ from nowhere in time, nowhere in space, nowhere anywhere else. I'm drawn to the first rather than the second of those.
But there's no sign of a purpose. Nor does the existence of self-replicating cells capable of evolving, and known to exist only in one place in a universe that may contain septillions of stars and however many planets that might imply, and which took 9 billion years to happen, suggest that life on earth is intelligently designed. (If it did, it would raise the question of where and how the designers evolved, of course.)
Ignorance does not logically default to non-existence. Not knowing does not presume not being. So if anyone wants to call this great existential mystery "God", and proclaim that "God exists", they most certainly can.
Yet as I've mentioned more than once before, there's no definition of god that's appropriate to a being with objective existence, no objective test that will tell me whether my keyboard is God or not. Devising gods is apparently something humans have evolved to do, either because such beliefs are good for survival and breeding, or because they're an artifact of other evolved traits.
Because the great existential mystery does exist, from our cognitive perspective.
But there is zero demonstrated necessity for the mystery to be solved outside of physics, the examination of the evidence of reality.