Have you written documents in raw TeX?

I’ve written book-length documents in Plain TeX (probably what you mean — nobody writes in “raw” tex) and in LaTeX. I would say that Typst, if it’s a replacement for anything, is a replacement for LuaLaTeX, because of its programmability. But in this article I framed it as a possible LaTeX replacement:

https://lwn.net/Articles/1037577/