Or find something to work on that you actually care about. I don't have any trouble working on something for 12 hours a day when I find it intrinsically interesting and meaningful.
I'm also a weirdo. I intensely dislike what I do for a living but I'm good at it and the money is pretty excellent. And I hate it enough to want to do a quality job of it and automate as much of it as possible so I can do something more interesting with my time instead.
How does this work in a full time job where you hate what you are doing? When you automate something, you're not freeing up time to do whatever you want. You're just freeing up time to do more of what you don't like, isn't it?
Doesn't work as well these days since most knowledge gets shared and a lot of devs are too eager to reveal their cards.
I strongly urge you to take the time to establish a long term pace that will allow you to regularly decompress from work, learning, and stress every single day as well as whole “step-away” moments for weeks at a time to allow you to completely disconnect at regular intervals throughout the year.
Based on your description, you’re young and your youth is powering this ability to keep going. Even if you take perfect care of your health, this energy will decline with age, more health complications will arise merely by being older, life will put more expectations on you, or conversely, a lack of life due to grinding too hard professionally will bring depression and loneliness.
Think carefully about how maintainable your perspective on work and life is for what will be at minimum the next 20 years.
Stay safe and take care of yourself.
I believe this is a myth. Excercising for 12 hours a day is not the best strategy to get your body and mind in shape for the Olympics. Internet sources claim that Olympics athletes train 5-7 hours a day. Pro football (soccer) players at top level, with absolutely insane amount of competition constantly breathing down their necks, usually train from morning till lunch and that's it. Doing more would only do harm.
I do appreciate you pointing out that this is a myth. It’s important people don’t think this is somehow manageable, even for “just a few years”.
All that being said… you’re still going to keep hearing it on the news, in books, from movie stars, etc…