The chiastic structure is present even if you don't choose to study it. My estimation the structure is cascading in 2 parts. Broadly the days 1-3 are organizing, separating where days 4-6 a filling up. 1:1 obviously paired with 2:1 which leaves 1:2 with 2:2-3 and when studied is a natural pair of contrasting darkness/light, empty/full, inform/formed, incomplete/compete etc...
A1 1:1-
A2 1:2-
B1 Day 1-
B2 Day 2-
B3 Day 3-
-B1 Day 4
-B2 Day 5
-B3 Day 6
-A1 2:2-3
-A2 2:1
Day 1 is a disembodied light, day 4 the bodies of light are created which feels a bit like the cart before the horse. The days are indeed ordered but in what way? Light spoken into darkness has undeniable spiritual application that the NT affirms, to start, Christ calls himself the light of the world but more directly we see the comparison in 2 Cor 4:6.
Light spoken into darkness is a salvation event (metaphorically) just as I was once of darkness and light was spoken into me. It is critical that light is first to know that no intermediary thing gives me the light and it is direct from God (of it were source from the sun I might be worshiping the sun). If the sun then it make more physical sense but the metaphor would fall appart. The account clearly has metaphor application (2 Cor 4:6 proves that) and there is a prioritization of the light first.
I frankly don't care much about the lit. application as I don't see it has much value. If it was a billion years, 6 days, or a single moment, from our perspective the earth, sky, sun, moon etc... are still here in the same way so nothing changes. The account itself is traditionally penned by Moses some 2500 years after the event so the perspective of the post-exodus Hebrews is the same. There are some non negotiables of course such as everything comes from God but how you approach the lit. application of the account is not something that has a lot of spiritual merit. I believe in God either way.
But the spiritual application is immense and once you stop forcing a lit. application and focus on the spiritual application different goals are revealed that show a beauty and intention in the order that the lit. can't do. I don't deny the ordering has purpose, but we need to establish the most important purpose of the account first before we can define it's order. We default to a lit. view and tends have an effect of only talking about the lit. application and not the spiritual application. I would rather not comment on the lit. application because it's so uninteresting and talk more about the spiritual application because it's so life giving.
I've picked apart the seven days of creation myself.
Even when the seven days of creation are enacted within my spiritual life, it is in sequence. When God creates, that's how He does it, it's a window into His personality.
Did you know that the time after the exiting of the garden mimics the Seven days of creation? (in sequence)
Even the end sequence in revelation is in numerical order.
The first era of humanity was the pre-flood, light and darkness scattered amongst the souls of humanity. By choosing one family to survive, this separated the light and the darkness.
The prophets speak of the nations as waters, the separation of heaven and the earth nations happened after this. In the early part of the old testament, all nations believed in the same God who later believed in other gods. This era also had a division of nations occurring. Moses leaving Egypt and separating the sea to escape on dry land, was the beginning of the third day, as the youngest nation was established at the end of an era.
The third day featured not only Moses separating waters and walking on dry land, it featured Elijah separating the river and Elisha walking through. The Elijah-Elisha story was fulfilled through John the baptizer's baptism of Jesus who was immediately taken to the Desert by the Holy Spirit. Jesus also died on the third day after being crucified.
The fourth day is alluded to by Daniel in which "Those who are wise will shine like the brightness of the heavens, and those who lead many to righteousness, like the stars for ever and ever." This speaks of our covenant, and the apostles.
The fifth day doesn't seem to be spoken of in Scripture. I could guess, but have to chalk it up to something only the Father knows.
The sixth day of the beast and the man are in Revelation, emphasis on the beast and the prophet being thrown into the lake of fire prior to the fulfillment of the seventh day.
The seventh day is that period described in Revelation 20 when Satan is sealed and cannot deceive the nations anymore. Since an era where the leaders of nations are
not liars has not come, this is yet to be fulfilled.
The garden sequence ended with a deception, a judgment, and the entering into a new world. The Revelation sequence is the same.
To those saying "so what?" the gospel conclusion to this is: When God saw what had happened to the heaven and the earth, He immediately began creating a new one .. since this one would eventually become uninhabitable for all life. God didn't have to, this is just part of who God is.
That is the reason the concept I have of the seven days remains constant within me. Not just for the spiritual benefits and foundation, but also because of who God is.