It is incredibly rare that people gain that elusive fulfilment via their career. It is in fact easier to achieve it outside of work constraints. Equally, when people regale me with the most interesting stories of their life, mostly it has nothing to do with their jobs.
I've had "careers". But I'm the happiest now in a smidgen above the minimum-wage part time job that allows me to fully shut the door on it at the end of the shift and leaves enough free time to actually do the things I love on my own terms.
I can't even say what I would study if I was to put myself through some higher education again. I'm just not inclined that way anymore. I will, however, take any number of building courses so I can crack on with the massive project that is my crumbling house. I enjoy it, it's challenging, it's rewarding, no two days are the same, I answer to myself, I can take off days as I please and I'm adding to my assets.
I am also painting art which has seriously taken off and can bring in more money than my current job does with just one painting. But I need to get the house done before I take the leap (one thing at a time!).
To achieve something, you just need to do something but it doesn't have to be your job or education.