All people contributing to Tinycore are volunteers.
The top priority is developing Tinycore and apps. A number of people are putting a lot of time and effort into that.
Anybody can contribute to the wiki, and many people have.
But like you say, it is incomplete and not up to date.
All contributions are appreciated. Anyone who has a good understanding and the time, is encouraged to contribute.
There is the possibility of making a help extension in the future. But the documentation should be up to date, complete, and to a professional standard first.
So please, use Tinycore, develop a good understanding, then contribute.