Then God made light twice, which seems redundant
It is not just redundant, it is absurd, it's illogical.
The Fourth day God created the Sun Moon and Stars. The first day God created the light of Heaven and separated the light and darkness, leaving the Earth in darkness to be lit by the Sun Moon and Stars.
Here, you are attempting to rationalise the absurdity.
The sun is older than the earth. And our star, the sun, is a young star. More ancient stars have existed billions of years before the sun.
Some of the stars that we can observed in our night sky, are older than the sun, because they have reach the stage of collapse, for instance, when it move off the main sequence star (fusing hydrogen at star's core), and become red giant (either fusing hydrogen from the shell surrounding the core or begin fusing helium the core into heavier elements, eg carbon, oxygen. When that happen the star will grow in diameter.
Red giant stars are stars that begin their decline, are older stars.
We know this because the Arcturus (Boötes constellation) is the closest red giant star, only about 36 light years away. This red giant is over 7 billion years old.
Our star is still fusing hydrogen, so it is still a main sequence yellow ward star. The sun is already 4.8 billion years old. In another 4 or so billion years from now, the sun will have the same fate as Arcturus. And when it does the red giant sun will consume mercury and possibly Venus too. And though red giant stars are cooler at the surface temperatures, it will still nbe hot enough burn or strip away the Earth's atmosphere, turning the Earth into a new Venus.
The fact, that there other red giant stars and white dwarfs that are close enough to be observe with naked eyes or hobbyist telescopes, show that that are much older stars out there, which debunk the Genesis notion that the Earth is older than the stars we can see.
Second, if the calculation of the Old Testament timeline is right, the Earth is no older than 6000 years, and yet there are stars and galaxies more distance than that.
Our nearest spiral galaxy, the Andromeda Galaxy is about 2 million light years away from our sun. If the earth and stars are less than 6000 years, then we shouldn't be able to see Andromeda yet.
Even though the speed of light is very fast, it will take 2 million years for the light to travel from Andromeda Galaxy to reach Earth. We should not be able to look at our sky, and see the the blurry blob to be that of Andromeda.
This also debunk the notion that creation of all the stars occurred on the 4th day of creation.