The pattern of "one request yields multiple kinds of responses" is challenging. You're basically looking at either having the client ask for the results and get

The pattern of "one request yields multiple kinds of responses" is challenging. You're basically looking at either having the client ask for the results and get them back, and then send the results to backend to get back the summary, OR, you're setting up some sort of sockets/server-sent-events thing where the frontend request establishes a connection and subscribes, while the backend sends back different sorts of "response events" as they become available.