e.g. your suitelet could return the map/reduce task id, and the client code that invoked the suitelet could periodically check the status of the map/reduce task to know when it finishes

there's no client script. a form is generated on request.

if you want the map reduce results in the browser you would need a client script to poll the status of the map reduce script and get its output (probably a file in the file cabinet) when it's finished

this is above my pay grade. 🤣

ha that's why the simple answer is no