One of the biggest issues Young Earth Creationism runs up into is all scientific evidence points the the Earth (and the universe) at the very least being older than 4000/5000 years old (or whatever the number is that they are using). The only creationist hypothesis that doesn't "
exactly" go against scientific evidence would be the Omphalos hypothesis.
https://en.wikipedia.org/wiki/Omphalos_hypothesis
This states that some thousand odd years ago, God created the universe in it's entirety, but created it with signs of great age. It's sorta like if you took a video and started watching it halfway through. Even though it "started" at he half way point, if you rewound, you'd go back past the "start".
So by this theory God, being all powerful of course, created the universe that at it's moment of creation was already 13 billion or so years old. If you "rewound" the universe, it would play out all 13 billion years of it's "false" history in reverse. By the Omphalos hypothesis, the universe created 4000/5000 years ago
would still be 13 billion years old anyways.
Obviously, the vast majority of people wouldn't think this is likely the actual case.
I could state that the universe actually popped into existence the moment before I started typing out this post, it's just that is so happened to come into existence with all the signs of being here much longer, such as all human memory, all the light already moving from distant stars, all the history books, all the buildings and roads and trees, and so on and so on. There's no way to prove that the universe did indeed pop into existence like that, but there's also no way to
disprove it.
And science can't 'work' with something that cannot be both proven or disproven. Science cannot confirm the existence or lack of a soul either, at this point we enter the realm of faith rather than science.
Science is grounded on what we can observe, what we can deduce, and what we can experiment with. If the universe was "created" 4000 years ago, but with all the signs of being 13 billion years old, then the universe is still 13 billion years old.
And no, I don't believe in the Omphalos hypothesis. I don't believe in YEC at all. I believe the universe is 13.82 billion years old (give or take a few), started at the Big Bang, and evolution is how we got to
Homo sapiens sapiens.