Worker best practices for receiving data?

Let’s say I have hundreds of objects that need to be updated from an external data source. I spawn a worker to fetch the data. I now want to update all my objects.

I assume there’s no way to update the objects in the worker and I need to return the values, parse them and assign them to the objects.

Do I return the data in JSON and parse it? Save it to a temporary DB to be read?

It feels like there’s going to be a lot of data processing outside of the worker. Am I actually making my app any more user responsive vs using a thread?

For reference, the kind of external data source I’m thinking about could be syncing with a cloud database, a desktop app like the Calendar or something like AWS.

I did some testing recently with workers. They choke badly if the data returned is too large. Bug is supposed to be fixed for the next version. I’d try with Json and if that doesn’t work with a text files. A temp db would need multiple read and write operations at the same time.