You are calculating all of this without time. The only point in time before matter exists is G-d’s time- which you don’t know two squirts about.
Time is anything between infinity to the snap of an electron depending on where you are and who you are. Don’t bother straining yourself over the math. The is no static time cycle in the observable Universe before it was even created.
Just stop and understand that from His point of view, it was a day- Not from the point of view of a planet, that didn’t even exist yet, spinning around a Sun, that also didn’t even exist yet. It’s pointless. You might as well ask a fish to calculate the veolicity of nuclear reaction in another Universe from a fish bowl. You simply can’t. You ain’t him.
Then again, the first chapter did a pretty accurate job of getting the nuclear physics and the astronomy and the geology and the biology right .....