Honestly I find “it’s unknowable” to be a pretty satisfactory answer. Mostly because to me it points at something that seems almost obvious the more I’ve thought about it. Even if it were possible to see past the “Big Bang”, what possible reason is there to think that would be the end of the rabbit hole? As mind bending as it is to think that the trail is infinite, it’s even more mind bending to imagine that it’s not.