Let's start with what you believe. If you do not believe something is eternal, then it seems you must believe at some point there was absolute Nothingness. Not essentially nothing, not virtually nothing, but absolute Nothingness. From that, it seems, something began.
I do not understand how something can come about from nothing. Can you explain that somehow?
By my way of thinking, certainly the universe may be eternal. Or possibly it came about from something else - oscillating universes, arising, retreating, arising, in endless cycles.
Unlike you, I believe there has always been something, the past is infinate, without beginning.
As to whether or not a creator adds a level of complexity, I do not see it that way. When I see a tree, I suppose there was a seed, then roots, then a stem. You might ask why all this complexity. There is a tree. Why must there be more of the history of the tree. Of course you do not. Trees begin with seeds (often, sometimes other methods, but never just suddenly just a tree). This is a natural progression. No reasonable person believes there has always been a tree.
Unlike you, I believe there always has been something. The decision is between a universe, or a creator. I
By my understanding, many Scientists say the universe had a beginning. They have no substantial clue what existed one second before the universe. That seems very complicated to me. They have to imagine there was something, matter, anti-matter, energy, some combination, but who knows. A complete unknown. Hardly simple, or it could be described.