Multiple QWebEngineProcesses created by QWebEngineView eats up memory

Question

In my application I have a list of buttons and clicking on each creates a new QWebEngineView in a QMainWindow. On closing the QMainWindow I want the QWebEngineView (and the QWebEngineProcess that it spawns) to be destroyed. But this does not happen - if I click on multiple buttons, multiple QWebEngineProcesses are created that eats up memory. Why are these processes not getting killed even after destroying the web view? Can anyone please help me with this?

Here is a sample code that I tried while trying to solve this problem. I have a single button here and clicking on it each time creates a new main window with a QWebEngineView.

import sys
from PySide6.QtWidgets import (QApplication, QWidget, QVBoxLayout, QPushButton, QMainWindow)
from PySide6 import QtCore
from PySide6.QtWebEngineWidgets import QWebEngineView


class PlotWindow(QMainWindow):
    def __init__(self, parent):
        """Constructor."""
        super(PlotWindow, self).__init__(parent)
        self.webV = QWebEngineView()
        self.webV.load('https://en.wikipedia.org/')
        self.setCentralWidget(self.webV)


    def closeEvent(self, event):
        self.webV.destroy() # => This does not kill background process QWebEngineProcess



class webView(QWidget):
    def __init__(self):
        super(webView, self).__init__()

        self.layout = QVBoxLayout(self)
        btn = QPushButton('Click')
        btn.clicked.connect(lambda: self.create_plot(self))
        self.layout.addWidget(btn)

        self.setLayout(self.layout)

    @QtCore.Slot()
    def create_plot(self, widget):
        win = PlotWindow(widget)
        win.show()


if __name__ == "__main__":
    app = QApplication()

    web = webView()
    web.show()

    sys.exit(app.exec())

I came across this : https://doc.qt.io/qtforpython-6/overviews/qtwebengine-features.html#process-models and "Process Per Site" might be a possible solution for this problem, but I really do not understand how and where to use the command line arguments. Just passing them as args to QApplication() doesn't work.