At Planck time there is no way the command “Light Be’ can manifest. If one calculates far enough ‘down’ they reach a point/moment when time is space and space is time, kind of like walking to the North pole and then keep walking and you will be headed toward the south pole. Therefore a period of inflation (the differentiating of dimension space and dimension time) created the spacetime where radiation can happen and underlies everything (the zero point field). Then The Creator spoke matter and thus worlds into existence.
Remember, the ancient Israelites had no idea just how vast and old the universe is. Heck, we didn't even know that there were other galaxies until a century or so ago. Therefore, when Genesis 1:1 says, "In the beginning, God created the heavens and the earth," it could be referring to the universe as we know it . . . but it doesn't have to be. To Moses "the heavens and the earth" where the part of the universe visible to his naked eyes, so it could be referring only to our home planet or solar system.
Alternatively, it could indeed be referring to the whole universe, but verse 2 skips over 13 billion years of cosmic history to focus on what was important to Israel, the creation of the world they actually lived on.
If this is the case, we note that before day 1 starts, we have an earth covered in a primordial ocean. According to Job 38 (at work so I don't have the exact verse on-hand), this primordial ocean was swaddled in thick clouds. Now, when God says, "Let there be light," the Hebrew is Yihi 'or, with yihi being the imperfect form of the verb hayah. Unlike bara, this verb does not mean that the subject never existed in any form before.
For example, in the story of Ruth, when Naomi finds out that Boaz looked out for her daughter-in-law, she says, "May he be (yihi) blessed." She's obviously not saying that blessing never existed in the universe before, nor even that Boaz had never been blessed before (he was, after all, a wealthy landowner). She was simply asking that the Lord's blessing be manifest upon Boaz for the good deed he had done.
In the same way, we can read, "And light was" (veyhi 'or) not to mean that light never existed anywhere in the universe before, but as meaning that God was now parting the enshrouding clouds so that light could manifest on the primordial ocean, thus beginning the process of preparing the heavens (in the sense of the sky or atmosphere) and the earth for life to exist.
Shalom