It's stated as thousands, but even then it's less precognition and more analysis. It's like Garou seeing King in the street, predicting dozens of outcomes, but gets kicked by Saitama instead. Her eye isn't future seeing, it's predicting possibilities.
And again, it's used far more for offense. Giving it to her based on defense sounds headcanon-y when it's literally described as the ability to reach what the user deems the perfect way of attacking.
So you're saying that what her eye foresees is possibility, correct? That doesn't make it inferior to Kenbunshoku foreseeing the next definitive attack based on your emotions and intent? There isn't a single instance of it being countered unless it's by other Kenbunshoku users who see the one definitive thing you're about to do.
Again, you're ENTIRELY mixing up future sight with analytical prediction, which is what her ability (and every mind's eye) is.