But think about McDonalds. The food is grown by "farmers", the buildings were built by construction workers, the people who work there were taught by teachers, and the food was created by scientists.
Some, but not all, of those people are doing meaningful work.
Now consider the banker that renegotiates mortgages with long time customers to help them stay solvent, the politicians who stand up for constituents, the salespeople who help people find a car that will really serve them well, the lawyer that takes a pay cut to defend the accused...
Meaning is not found in what you do, but how you do it.