You can add a flag in a singuler entity /in configuration that microflow is running and if its true u can close the task queue microflow without further processing.
singuler entity or configuration part: create an persistent entity with boolean attribute.in task queue use a getOr create microflow and check for flag
when task queue microflow starts set it to true and in the end set it to false
You could save succes/failed in some boolean attribute in an object that you retrieve in your queued microflow before executing.
Or put only one file in the queue instead of all of them in the loop. If the queued microflow is successful, at the end of it you could retrieve and queue the next file.