Time is a way of formatting experience. But all experience does and can only ‘occur’ NOW. (Everything we feel and think, we feel and think NOW.)
Our world is a reflection of who we are (it has to be because we are inherent to it), and since we understand everything as ‘coming from’ something that makes the Big Bang, as an example, as much metaphor as theory. ‘Coming from’ something gives us meaning, and thus morality. (If everything came from nowhere then what is the meaning of anything? Where is the morality?)
(Before the Big Bang theory arose, we pretty much all came from god. Both explain everything as ‘coming from’ something. It occurs to me that we could extrapolate from that and say that god is about the morality of where we came from, while the Big Bang focuses morality on where we are going. But that's me thinking out loud!)
If it is to be, at all, it must all be NOW. In that sense, yes, everything does occur ‘simultaneously’!
Thanks for the read!