"force yourself to work on something that you don’t see the value in."
Not really, that sounds more like the definition of being an employee (without equity etc).
Although I guess many employees find reward in the job itself and in the "progression" up the career ladder that business owners put in place.
I don't think it's merely a case of work-life balance. It's possible to sustain a nominally very skewed work-life balance if you enjoy the work and the people you work with, and you have a real stake in it (either equity, really building your own skills, saving the world, whatever).
But if you lose joy in the day to day work itself, and especially start to see through the "career-ladder" or "office-perks" BS then you will feel burnt out, whether you've been putting in 12+ hour days or not.