It's 2024. Why my freaking document scanner app still doesn't have this built-in?
This is a good YC-sized problem - weeks to market, a few hundred thousand dollars to launch. Apple has a phone app for this which requires too much manual adjustment, and Microsoft has Office Lens / Microsoft Lens, which has comments such as "The edges just eventually go crazy and look horrendous". So there's a market for one that Just Works. Exit by selling to the usual suspects.