“Day” doesn’t mean “epoch.” It means “day.”
Believe otherwise if you like. You seem to intent on believing this. Why? Why not just accept the word of God for what it says? This is not a complex passage.
Why I believe what I do? Besides how I understand science, I see God, as I was raised to see Him: As the Creator of a universe that is billions of years old, subtle and marvelous in how seemingly simple systems can develop remarkable complexity, so that from a single-celled creature, creatures in the Image of God may arise. I see a universe of just not human beings, but of thousands, maybe millions of intelligent species, all in the Image of God, all praising God in their own ways and God enjoying the praise from each and every one of them.
That is how I imagine God, who I worship.
In comparison, the god (I can hardly call it "God") of creationism is puny thing, having created only 6000 years of history and one species to praise him and having done so with all the grace of a cow turd.
I don't believe that any mortal can imagine more than God can create. I don't imagine God would create a universe that did not encompass as much as He could put in it. If the imagination of a mortal scientist is more spectacular than God's creation, then shame on God.
I believe that God is better than that.
And the word of God says that He is better than that. It says that a thousand of years to us is like a few hours (a watch in the night) to Him -- that God's experience of time is different than ours. A "day" of God is not a day of a human species.
So why don't you accept the word of God for what it says in its entirety, rather than just a few isolated sentences, and see how much grander than mere creationism God's universe is?