There may be others.Yea, our space time. Our one little bubble in an infinite sea of bubbles.It’s a given that our space time is not eternal into the past.Maybe this universe exists in an infinite amount of space and time? Think about a lava lamp.
If god is eternal so is space and time.
The whole point of the KCA is that spacetime cannot be eternal. You're alleging an infinite regress of causality or an actual infinite of materiality. Please give a coherent account as to how such things are possible. Also, are you equating divinity to a material being?
If we start from the position that our existence had a beginning and was created from nothing according to the laws of nature then we know that the laws of nature existed before our existence. Which supports the assertion that existence can only be created by a preexisting existence as the laws of nature were already in place.
But if there are they each had a beginning.