So many things annoy me about this sort of self-help guru vagueness.

"One thing I know is that if you want to do great things, you'll have to work very hard" - this is not true. You have to work, but the "hard" part implies that stress is important. Stress is incidental - everyone experiences stress regardless of work. I learned years ago that high achievers don't experience more stress... an in fact they tend to rephrase problems to give them LESS stress. They work, but they purposely make those things less stressful. The work itself, from their perspective isn't "hard" at all.

"There are three ingredients to great work: natural ability, practice, and effort". These aren't separate things! Natural ability is learned just like anything else. It's a set of skills that you develop through building your own ways of thinking. You get those through practice. And for some, that effort is often negligible for one reason or another - experiences and thoughts that they have because of emotions or places they grew up or what context they relate to. I could go on for hours about this specific topic.

"And yet Bill Gates sounds even more extreme. Not one day off in ten years?" - A surprising number of people do this anyways. If it's not stressful to them, it's not effort... it's just what you do. By the way, most of these people don't become rich. Why? It's not because of "natural ability" or "lack of practice and effort". It's because their daily work covers things that aren't, directly, money. "Cows got to get fed" or "lawn has to be mowed" or "kids need to be watched" or "spend a bit of time on something that I actually like". For Bill Gates, that "just what you do" was probably "work on microsoft". And if it failed, he's publically said that yeah, his backup plan was to go back to Harvard, becuase that was of course an option for him. Relatively speaking, it wasn't a super high risk decision.

"Now, when I'm not working hard, alarm bells go off. I can't be sure I'm getting anywhere when I'm working hard, but I can be sure I'm getting nowhere when I'm not, and it feels awful". This sounds, honestly, quite unhealthy. It's "feel pain now because reasons. I have multiple theories on how this sort of thought process comes around. For example, When we can't relax during our downtime, or we don't actually get the rewards of our labor.

But you notice that outside of constructed work environments (like school, or any job where you have a direct boss), this doesn't happen. Those who practice violin practice until they're done practicing, then they relax, then they come back later and practice some more. They don't half-ass practice, because there isn't a point to that. If you're practicing, it's not "so that I can work hard, and if I don't I feel guilty". Instead it's "I need to polish this one part of the song" or "I'm struggling with my fingering here" or maybe even "I'm going to play with this section of the song, it seems fun". Note - it's not pointless work. So "I'm working, but not working hard" just... doesn't happen. Because why would it? That doesn't make the song better, it doesn't make you better.

The more I go through the article, the more I just think the goals are getting tripped up by a combination of external forces that take up mental resources, and a mental model where the stress of the situation determines the quality of the product.

I have tons of suggestions (I trimmed this comment down and rewrote it 3 times already). The big one though I think is learning to roll with what matters. Do everything you're doing, and then take a break, and then do it again. Honestly, unless you get into the nitty gritty details, It's really a lot simpler than people think.