How to run a class in a separate process?

Question

Python

At the moment, my program is released with a thread launcher. But the problem is that in principle it is impossible to control the flow until the final result arrives.

Here is the implementation of my flow

def threadIbazar(self):
        self.ui.parserButton_sk_4.setEnabled(False)
        self.ui.parserButton_sk_4.setText('Сканування запущено')
        self.thread_4 = QtCore.QThread()
        self.parserIbazar = ParserIbazar()
        self.parserIbazar.moveToThread(self.thread_4)
        self.parserIbazar.newTextSignalIbazar.connect(self.addNewItemIbazar)
        self.thread_4.started.connect(self.parserIbazar.run)
        self.thread_4.start()

How can I do this as a process? So that I can calmly stop it at any time using the "Pause" button, without pitfalls. By stones, I mean the banal closure of the program now. If my stream is running and I close the program, then some of the files with which I work are simply erased. So I kill the program somewhere halfway through the cycle.

At the moment I have 16 such threads