The short answer
Meaning isn't a property of the work itself — it's something you construct by connecting what you do to what you actually value. Research on work meaning backs this up. The thread you're looking for runs through you, not through the job description.
You're waiting for the work to hand you meaning. But research on how people find meaning at work is clear on this: meaning isn't baked into a role or a task. It comes from the connection between what you do and what you care about. When that link is fuzzy or unexamined, even good work feels hollow.
Marcus puts it plainly — what drives a person isn't the external thing, it's what's going on inside, in their own judgments and values. The thread you're looking for is already in you. It's not something the work will give you. It's something you bring to the work once you know what you actually stand for.
This week, try this: write down three moments from your work — recent or past — where you felt, even briefly, like it mattered. Don't filter. Then look at what those three moments have in common. That pattern is your thread. Once you see it, you can start pulling it through more of what you do.