Purpose is discovered by doing, not decided in advance. People wait for it to arrive as a conviction, then feel defective when it doesn't show.
It turns up in retrospect — in the shift you volunteered for and lost track of time during, in the problem you keep drifting back to when nobody's assigning you anything.
Giving yourself completely is a bigger ask than most weeks can carry. Start by giving something your full attention for one afternoon, and see what it gives back.