Atheists don’t view the existence of God as proven fact— just that it’s so improbable, so unknowable, so unprovable, that it’s not at all worth considering. It’s not provable either way, which is the point. If it’s not provable, the default position is “unproven.” No proof of unicorns and they are improbable, therefore it’s unproven and not worth serious consideration.
As you like.