One theistic evolution or old-earth creation theory is that on the third day, God created plants in different points of time, and on the fourth day, God placed the sun, moon, and stars into a time before plants. On the fifth day, God created fish in a point of time before fruit trees were created. Six days were literal but outside of time. I call this the non-linear-time creation theory.
Another theory is that there were two timelines, one with billions of years of evolution, and one of six thousand years after six-day creation, and the two timelines merged. In the past, they were separate, and sometime after the flood in the six-thousand year timeline, the two timelines merged. Like continuities in the Marvel and DC Multiverses merge, even though both those are fictional, God in real life could do the same as in those fictional universes because he’s all-powerful. I call this the split-timeline creation-evolution theory. Or merged-timeline creation-evolution theory.
Edit: the second of those two theories is also like a fan theory of The Legend of Zelda: Breath of the Wild. As the two timelines (adult link and child link) merged (at least according to a fan theory) in that fictional story, God could do the same in real life because he’s all-powerful.