Qt 6.8 QML resize Jitter, bad performance

[Edoardo_P]

Hi,
I am developing on windows 10 a Qt 6.8 application with Qt Quick and I am encountering some problems. I wrote the following code, but I can't get it to work properly and it gives me the error you can see in the gif below:

I'm using windows 10 and this is the full code:
main.qml

import QtQuick
import QtQuick.Window
import QtQuick.Controls
Window {
    color: "white"


    width: 1280
    height: 720

    visible: true

}

main.cpp

#include <QApplication>
#include <QDateTime>
#include <QDir>
#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QQmlContext>
#include <QStandardPaths>
#include <QString>
#include <QTextStream>
#include <QVector>

int main(int argc, char *argv[])
{
#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
    QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps); //HiDPI pixmaps
#endif
    QApplication app(argc, argv);

    QQmlApplicationEngine engine;

    const QUrl url(QStringLiteral("qrc:/main.qml"));

    QObject::connect(&engine, &QQmlApplicationEngine::objectCreated,
                     &app, [url](QObject *obj, const QUrl &objUrl) {
        if (!obj && url == objUrl)
            QCoreApplication::exit(-1);
    }, Qt::QueuedConnection);

    engine.load(url);
    return app.exec();
}

project.pro

QT      += quick
CONFIG  += c++17
QT      += qml
QT      += network
QT      += quickcontrols2
QT      += widgets
QT      += core gui
QT      += multimedia


DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x050F00

# You can make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

CONFIG += app_bundle



SOURCES += \
        main.cpp 

RESOURCES   += ui.qrc

# Additional import path used to resolve QML modules in Qt Creator's code model
QML_IMPORT_PATH =

# Additional import path used to resolve QML modules just for Qt Quick Designer
QML_DESIGNER_IMPORT_PATH =

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

HEADERS += 

Do you have any suggestions on what I can correct or improve? Thank you in advance!