QPainter debug builds on Windows very slow

#include <QApplication>
#include <QWidget>
#include <QPainter>
#include <QElapsedTimer>

class Widget : public QWidget
{
public:
    Widget();

protected:
    void timerEvent(QTimerEvent*);
    void paintEvent(QPaintEvent*);

private:
    QElapsedTimer elapsedTimer;
    int timerId;
    int elapsedTime = 0;
    bool isFinished = false;
    double i=0.0, x=40.0, y=0.0, y2=30.0;
    QPen Pen = QPen(QColor(0,0,0), 8);
    QFont Font = QFont("Arial", 14);
};

Widget::Widget()
{
    setAutoFillBackground(true);
    setPalette(Qt::white);

    timerId = startTimer(1);
    elapsedTimer.start();
}

void Widget::timerEvent(QTimerEvent*)
{
    update();
}

void Widget::paintEvent(QPaintEvent*)
{
    QPainter painter(this);

    if (i >= 0 && i < 3770) {
        y = 30.0;
        painter.setPen(Pen);
        painter.drawLine(x-20.0, y,       x+92.0, y);
        painter.drawLine(x-20.0, y+570.0, x+92.0, y+570.0);

        for (int j=0; j < 550; j=j+30) {
            painter.drawEllipse(x-40.0, y2+j, 30.0, 30.0);
            painter.drawEllipse(x+85.0, y2+j, 30.0, 30.0);
        }

        painter.setFont(Font);
        painter.drawText(x, y += 20.0, "");
        painter.drawText(x, y += 20.0, "QPainter");
        painter.drawText(x, y += 20.0, "MSVC");
        painter.drawText(x, y += 20.0, "16.8.3");
        painter.drawText(x, y += 20.0, "debug");
        painter.drawText(x, y += 20.0, "builds");
        painter.drawText(x, y += 20.0, "run");
        painter.drawText(x, y += 20.0, "8");
        painter.drawText(x, y += 20.0, "times");
        painter.drawText(x, y += 20.0, "slower");
        painter.drawText(x, y += 20.0, "on");
        painter.drawText(x, y += 20.0, "Windows");
        painter.drawText(x, y += 20.0, "than");
        painter.drawText(x, y += 20.0, "release");
        painter.drawText(x, y += 20.0, "builds");
        painter.drawText(x, y += 20.0, "using");
        painter.drawText(x, y += 20.0, "Qt 6.0");
        painter.drawText(x, y += 20.0, "");
        painter.drawText(x, y += 20.0, "Prior");
        painter.drawText(x, y += 20.0, "Qt");
        painter.drawText(x, y += 20.0, "versions");
        painter.drawText(x, y += 20.0, "run");
        painter.drawText(x, y += 20.0, "only");
        painter.drawText(x, y += 20.0, "little");
        painter.drawText(x, y += 20.0, "faster");
        painter.drawText(x, y += 20.0, "on");
        painter.drawText(x, y += 20.0, "Windows");
        painter.drawText(x, y += 20.0, "");
        painter.drawText(x, y += 20.0, "");
        x = x + 0.2;

        elapsedTime = elapsedTimer.elapsed();
    }
    else {
        isFinished = true;
    }
    i++;

    if (isFinished) {
        painter.setFont(QFont("Arial", 14, QFont::Bold));
        painter.drawText(QPoint(320, 280), "Elapsed time: " + QString::number(elapsedTime/1000.0) + QString(" seconds"));
    }
}

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    Widget widget;
    widget.resize(900,640);
    widget.show();
    return app.exec();
}