Yup. This question has "plagued" humanity since... well, forever! Right? There is not an answer. Not only has it never been solved, it never will be. It's the very nature of it. Individuals can come up with something that gives meaning to their life (or not!). Even for those that believe they must come up with something, if they come up with only one, personally, I think they are deluding and limiting themselves. The world is much too complex for that. Not only that, but they torment themselves unnecessarily trying to find IT.

This is not to say that one shouldn't consider where one's passion and energy should be devoted. As for fear of doing something because it may have an unintended consequences? Ummmm, no one escapes this reality, and you are no exception! Sorry. All any of us can do is our best, and approach things with honesty and good intentions. There IS no perfection, and, as you are finding, you will immobilize yourself in thinking there is (even if you don't recognize it as perfection-seeking). Ease up on yourself. There's a helluva lot of gray in the world, and no amount of thinking is going to change that. Just begin on a path that appeals. Pick and go. Don't overthink. No one can see the future. We negotiate it as it comes. Not before, because we can't know everything that is going to happen. Including how our own perceptions and therefore, philosophies and goals will shift. That's just the way it is.