You have to figure out how to work hard without burning out. People find their own strategies for this, but one that almost always works is to find work you like doing with people you enjoy spending a lot of time with.
I think people who pretend you can be super successful professionally without working most of the time (for some period of your life) are doing a disservice. In fact, work stamina seems to be one of the biggest predictors of long-term success.
One more thought about working hard: do it at the beginning of your career. Hard work compounds like interest, and the earlier you do it, the more time you have for the benefits to pay off. It’s also easier to work hard when you have fewer other responsibilities, which is frequently but not always the case when you’re young.