I think the 1000 years was a basic reference and I have never seen a million or billion years and I have read the Bible through many times, but if you can find it....I will apologize.
Obviously I can’t find it because it was written during a time when people could not conceive of a number bigger than 10,000.
If God had told people the universe was 14 billion years old it would have meant NOTHING to them. So why confuse them.