pyqt subprocess stdin

import sys
import subprocess
from PyQt6 import QtWidgets, uic
from PyQt6.QtCore import QObject, pyqtSignal, pyqtSlot, QThread


class Action(QObject):
    runProcess = pyqtSignal(str)

    @pyqtSlot()
    def RunProcess(self):
        self.process = subprocess.Popen(["nmap\\ncat.exe", "-lvkp", "666"], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.STDOUT,
                                   creationflags=0x08000000, universal_newlines=True, encoding="utf8", errors="ignore")

        self.i = 0
        while (True):
            if self.process.poll() is None:
                output = self.process.stdout.readline()
                print(output)  # for debugging
                prettyOutput = output
                window.chat_console.insertPlainText(prettyOutput)
                QtWidgets.QApplication.processEvents()

            else:  # if the process is dead it breaks the loop
                break
            print(self.i)  # debug
            self.i = self.i + 1


class MainWindow(QtWidgets.QMainWindow):
    def Send(self):
        print("tried to write into stdin")
        self.action.process.stdin.writelines("test\n")  # trying to write to stdin
        self.action.process.stdin.flush()  # hoping that flush would write

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        uic.loadUi(f"gui.ui", self)

        self.show()

        self.action = Action()
        self.thread = QThread(self)
        self.action.runProcess.connect(Action.RunProcess)
        self.action.moveToThread(self.thread)
        self.thread.started.connect(self.action.RunProcess)
        self.thread.start()

        self.send_button.clicked.connect(lambda: self.Send())

    def closeEvent(self, event):
        y = self.action.i  # saves the number of the current loop
        self.action.process.terminate()  # kills the subprocess
        while(True):  # make the program wait and not quit too early
            if self.action.i > y:  # checks if the current loop number is higher than saved
                self.thread.terminate()  # kills the thread if the loop stopped
                exit()  # nicely ends the process


app = QtWidgets.QApplication(sys.argv)
window = MainWindow()
app.exec()