It is an enormous effort (read investment) to get to a point of detail, where such a library becomes usable to a wide audience.

Consider a simple text input: In some languages (e.g. 'syllable based' korean Hangul) you have to compose multiple keystrokes to get to a complex letter. While you type, the last and as well as the second-to-last complex-characters might still 'trade' consonants and vowels among each other.

Now layer in more Dimensions, such as validating that input or line-wrapping, elision and many more.

To my mind, only few libraries got to this level of detail without breaking apart on complexity. It requires high maintainer stamina or massive investments.