I am always surprised when someone says they are an atheist yet believe they have a conscience (which can not be “proven” as an organ or existing at all in our body). :)
C.S. Lewis began as an agnostic... which actually sounds to me more like what you are.... but, hey, I’m surely not God!
It’s a chicken-egg thing. I say morals were developed by societies as a way to work together and become stable. Care for others in a society being necessary to the strength of that society was even written about by Darwin. He didn’t apply genetic natural selection to humans because he knew it, a.k.a., eugenics, wouldn’t work due to our social nature. Over time these basic rules of interaction were codified into various religions as morals, commandments from God.