Purpose is strengthened by being useful where usefulness matters.

Usefulness in general is diffuse. Usefulness where it matters, where the absence of your effort would leave something worse, is what actually feeds a sense of purpose. The distinction is not about scale. It is about whether the need was real.

Check whether the place you are being helpful actually needs help. It is possible to be diligently useful where nothing depends on it. Move some of that effort somewhere the need is real and see what changes.