The "component.create()" function does not lead to a visible qml element

I want to instantiate a simple qml file with a rectangle through c++ . Unfortunately nothing shows up. I have no idea what the problem could be, the out-commented error printing shows no errors.

This is the Source Code:

#include <QGuiApplication>#include <QQmlApplicationEngine>#include <QQmlComponent>#include <QFile>#include <QDebug>int main(int argc, char *argv[]){#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);#endif    QGuiApplication 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);    QQmlComponent component(&engine, QUrl::fromLocalFile("C:/Workspace/QT/QMLPlayArea/InstantiableObject.qml"), engine.rootObjects().first());//    if (component.status() != QQmlComponent::Ready) {//        if (component.status()  == QQmlComponent::Error)//            qDebug() << "Error loading component:" << component.errorString();//        return -1;//    }    QObject *object = component.create();    object->setProperty("width", 500);    object->setProperty("height", 500);    object->setProperty("color", "red");    return app.exec();}

The QML main.qml is the default when creating a new project. the InstantiatableObject.qml is :

import QtQuick 2.14Item {    Rectangle{        width: 100        height: 100        color: "red"    }}