> Just look at North Korea for example ... on average their literacy is terrible.

Where do you get that information from? According to the CIA, it's 100% (https://www.cia.gov/the-world-factbook/about/archives/2023/f...). North Korea Info (https://www.northkoreainfo.com/why-does-north-korea-have-a-h...) gives a slightly lower estimate of 97%-99%.