I would add from my experience that writing and thinking are not mutually exclusive. I am constantly sketching out thoughts and ideas, which I later come back to and reuse or rewrite. Writing can be used an extension of your working memory.
In Hemingway's case [1] "writing" is equivalent to "coding"/"building", when in your case "writing" is more like "sketching out thoughts and ideas" with pen and paper.
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[1] “My working habits are simple: long periods of thinking, short periods of writing.”
-- Hemingway
I really enjoyed listening to Cal on the Lex Fridman podcast a few weeks ago.