PyQt5 WebEngine does not display pages like angular.dev or react.dev properly

I can't figure out how to make pages like react.dev, angular.dev, facebook.com, or chat.openai load properly.

from PyQt5.QtWidgets import *from PyQt5.QtGui import *from PyQt5.QtCore import *from PyQt5.QtWebEngineWidgets import *# Define a class MyWebBrowser that inherits from QMainWindowclass MyWebBrowser(QMainWindow):    def __init__(self, *args, **kwargs):        # Call the constructor of the base class (QMainWindow)        super(MyWebBrowser, self).__init__(*args, **kwargs)        # Create the main window and set its title        self.window = QWidget()        # Create a horizontal layout for the main window        self.layout = QHBoxLayout(self.window)        self.layout.setContentsMargins(0, 0, 0, 0)        # Create a QWebEngineView widget for displaying web content        self.browser = QWebEngineView()        self.layout.addWidget(self.browser)        # Access the settings of the web engine        self.settings = self.browser.settings()        # Enable JavaScript in the web engine        self.settings.setAttribute(QWebEngineSettings.JavascriptEnabled, True)        # Set the initial URL to "https://react.dev"        self.browser.setUrl(QUrl("https://react.dev"))        # Define a mobile user agent string        self.mobile_user_agent = ("Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36"        )        # Set the user agent for the web page        self.browser.page().profile().defaultProfile().setHttpUserAgent(self.mobile_user_agent)        # Set the layout for the main window        self.window.setLayout(self.layout)        # Set the default size for the main window        self.defaultSize = QSize(500, 800)        self.window.setFixedSize(self.defaultSize)        # Show the main window        self.window.show()# Create a QApplication instanceapp = QApplication([])# Create an instance of MyWebBrowserwindow = MyWebBrowser()# Start the application event loopapp.exec_()

I hope the mentioned pages load and function properly; for instance, the button to switch to the dark theme on React doesn't work, or the background of Angular doesn't display.