Thanks for your work. My issues were exclusively stuff like this page here: https://open-spaced-repetition.github.io/ts-fsrs/interfaces/...
It is great to have the docs well organized like this, what is missing is just a short explanation of what all those mean. The information is available, e.g. in the README or in the source code. So honestly it is just a minor annoyance, rather than a major issue. I was able to use ts-fsrs just fine actually.