I doubt Epicurus would go much past that without stating that "the universe / the all" must be eternal, because it is inconceivable that there was ever a time in which "the all" did not exist. It certainly appear to us that the we exist, and that it makes no sense to consider that there was ever a time that the all did not exist, so I would rule out of hand any supposition (it would require an infinite number of steps to get here and that's not possible) that conflicts with what all appearances tells us does exist.
Yes, I am going to use the universe to refer to “the all that exists”.
Well I guess I’m going to introduce wordplay that people who believe the Big Bang in the beginning do, so forgive me haha.
But I guess we could say that there was never a time where the universe didn’t exist, because if there is a finite amount of time in the past, the time before the first moment isn’t actually a moment in time. So the time before the universe didn’t exist, so in all moments of time the universe existed.