You may not need to discover a grand purpose before doing something genuinely worthwhile.

Waiting for a grand purpose before acting is a way of doing nothing while feeling serious about it. Worthwhile things are available at small scale immediately, and doing them tends to clarify direction far more effectively than continued reflection. The grand version, if it comes, arrives through the small ones.

Choose something genuinely useful you could start this week without resolving any large questions. Do that. Direction is more often discovered in motion than in advance.