For what it’s worth, the deepest-thinking and most profound programmers I have met—hell, thinkers in general—have a peculiar tendency to favour pen and paper. Perhaps because once their work is recognised, they are generally working with a team that can amplify them without needing to interrupt their thought flow.
Ha, I would count myself among those if my handwriting wasn't so terrible and I didn't have bad arthritis since my youth. I still reach for pen and paper on the go or when I need to draw something out, but I've gotten more productive using an outliner on my laptop, specifically Logseq.
I think there's still room for thought augmentation via LLMs here. Years back when I used Obsidian, I created probably the first or second copilot-for-Obsidian plugin and I found it very helpful, even though GPT-3 was generally pretty awful. I still find myself in deep flow, thinking in abstract, working alongside my agent to solve deep problems in less time than I otherwise would.