My attitude is it (meaning) is entirely sensory, not rationalized, and elicited through action. Bias, then, towards action. There's also no reason to believe that some obscure as-of-yet discovered vocation is the only thing that could grant meaning. Realistically, you could find all sorts of jobs meaningful. If you don't have a peculiar obsession, so be it. I dislike the term purpose.
Dull work with lots of lulls, or lots of passive consumption, or too little social contact won't usually equate to a sense of meaning. And real-world impact of your work won't really matter here, because that is just an abstraction. If you find "flow" in work, you'll feel what people peg as sense of meaning. You might also from receiving gratitude in-person for your help - it feels good. We're social beings. If you've ever tried the self-shaming route of rationalizing that you "ought" to be content with your lot, you'll know from experience that does not stick. That is not how our monkey brains work. If something feels bad, that's symptomatic.