A good way to think of creative writing, if you're a technical writer, is to imagine attempting to write a textbook when you don't know the subject at all, and the "demand" from each new paragraph causes you to do the research necessary to acquire the knowledge necessary to write it.
How would you even structure a thing like that, in advance?
How would it ever attain a sensible shape if done a paragraph at a time, when something you learned while doing the research necessary to write paragraph 100 invalidates everything you wrote before it, or causes a complete restructuring of your mental model such that you realize the topic should be presented in an entirely different order? (And then you realize that again, and again, and again...)
A similar thing occurs in investigative journalism. How would you know how to present a story—know what story you're telling, really—before you know all the key facts? In est, before you've completed your investigation? You could certainly write notes about what you might write, but those have little to do with drafting the final story.
I'm not really a big outline person either for either writing or presentations. I almost always have some idea where I'm going though it's not unusual for that to diverge.
I very rarely know what I'm going to write until I start writing. I don't even outline anything. I just start writing and relentlessly edit as I go.
I do the same thing for 1,000 word blog posts as I do with 400,000+ word course scripts.
If anything editing is more important for the larger pieces of work because in order to cleanly flow to the next lesson or section of a course the prior stuff has to be pretty much in its final form.