That sounds too much like three weeks of work saving you three hours of planning.

In my experience, software engineering is a matter of knowledge. Understanding it and then coming up with a solution. The latter is a flash of insight that comes mostly from experience. Then you gather more information to flesh it out, or brainstorm it with your colleagues.

What you're describing sounds more like a ritual of doing busy work than anything practical. Because tasks vary so much. A feature may be huge, but you take care of it in a day with copy pasting because you already have all the building blocks in other files. And something may be twenty lines of code, but you spent the whole week sweating on it (concurrency stuff maybe). Those ritualistic workflows sounds more like someone imagining software development than actually doing it.