Thanks for the response, Roelof.
I think you’re hinting at a universal truth here — that everyone is different, and has their own unique combination of factors that determine how they’ll be the most engaged and productive. Perhaps your best strategy to produce deep work isn’t any single one of these 4, or perhaps some combination.
There is discipline and self-restraint in deep work, too— it can be tempting to focus on too many things, or take breaks, or even just stop entirely. If you can focus more, that great. How do you think discipline and grit plays into your ability to prevent tunnel vision?