I was looking at:
https://cloud.google.com/retail/docs/export-data-into-bq
(If there is another download api you are looking at, let me know)
However, if it is that endpoint, or something similar, you can use HTTP Request or Multi HTTP Request to download results from Big Query.
With HTTP Request, you can do one at a time, with Multi HTTP Request (as the name implies) you can do multiple requests, at the same time. That is, with multi, the time it takes is the time it takes for the longest request and with the single http request, it's the total time for all requests.