Issues with QStyleHints colorScheme: ColorScheme.Unknown and colorSchemeChanged Signal not working

# This Python file uses the following encoding: utf-8
import sys
from pathlib import Path

from PySide6.QtWidgets import QApplication
from PySide6.QtQml import QQmlApplicationEngine
from PySide6.QtGui import QStyleHints
from PySide6.QtCore import Qt

import threading
import time

def print_hello_world():
    hints = QStyleHints()
    while True:
        print(hints.colorScheme())
        time.sleep(1)

t = threading.Thread(target=print_hello_world)
t.daemon = True
t.start()

if __name__ == "__main__":
    app = QApplication(sys.argv)
    engine = QQmlApplicationEngine()
    hints1 = QStyleHints()
    hints1.colorSchemeChanged.connect(lambda: print("hi"))
    qml_file = Path(__file__).resolve().parent / "main.qml"
    engine.load(qml_file)

    if not engine.rootObjects():
        sys.exit(-1)
    sys.exit(app.exec())

Window {
    id: root
    width: 800
    height: 600
    visible: true
    title: qsTr("Test")

    Material.theme: Material.System
    color: Material.background
}