We see your need. Please give us some time as first of all we are aimed to spruce up web app (make it perfect) and only after that switch to mobile applications.
The last also is not easy. There are too many bad trackers and we want to be different.
It would be just perfect to have a persistent notification with a stop button if a task is running.
Please help us better understand your necessity here. How do you expect it to work? What problems it’s gonna solve?