The quality of font rendering has dropped dramatically since version 6.8

#include <QApplication>
#include <QLabel>
#include <QVBoxLayout>
#include <QWidget>

const QString CONTENT_EN = "Qt empowers productivity across the entire product development lifecycle";
const QString CONTENT_CN = "Qt 赋能整个产品开发生命周期的生产力";
const QString CONTENT_JP = "Qt は製品開発ライフサイクル全体にわたって生産性を高めます";

class CaptionLabel : public QLabel {
public:
    explicit CaptionLabel(const QString& text, QWidget* parent = nullptr) : QLabel(text, parent) {
        setStyleSheet("font-family: MicroSoft Yahei; font-size: 12px; font-weight: Regular");
    }
};

class BodyLabel : public QLabel {
public:
    explicit BodyLabel(const QString& text, QWidget* parent = nullptr) : QLabel(text, parent) {
        setStyleSheet("font-family: MicroSoft Yahei; font-size: 12px; font-weight: Regular");
    }
};

class BodyStrongLabel : public QLabel {
public:
    explicit BodyStrongLabel(const QString& text, QWidget* parent = nullptr) : QLabel(text, parent) {
        setStyleSheet("font-family: MicroSoft Yahei; font-size: 14px; font-weight: Bold");
    }
};

class SubTitleLabel : public QLabel {
public:
    explicit SubTitleLabel(const QString& text, QWidget* parent = nullptr) : QLabel(text, parent) {
        setStyleSheet("font-family: MicroSoft Yahei; font-size: 20px; font-weight: Bold");
    }
};

class TitleLabel : public QLabel {
public:
    explicit TitleLabel(const QString& text, QWidget* parent = nullptr) : QLabel(text, parent) {
        setStyleSheet("font-family: MicroSoft Yahei; font-size: 28px; font-weight: Bold");
    }
};

class TitleLargeLabel : public QLabel {
public:
    explicit TitleLargeLabel(const QString& text, QWidget* parent = nullptr) : QLabel(text, parent) {
        setStyleSheet("font-family: MicroSoft Yahei; font-size: 40px; font-weight: Bold");
    }
};

class DisplayLabel : public QLabel {
public:
    explicit DisplayLabel(const QString& text, QWidget* parent = nullptr) : QLabel(text, parent) {
        setStyleSheet("font-family: MicroSoft Yahei; font-size: 68px; font-weight: Bold");
    }
};

class Win : public QWidget {
public:
    explicit Win(QWidget* parent = nullptr) : QWidget(parent) {
        setWindowTitle("Qt 6.8.1 Font Rendering with MicroSoft Yahei");

        // Create labels
        auto captionLabel = new CaptionLabel(CONTENT_EN, this);
        auto captionLabelCN = new CaptionLabel(CONTENT_CN, this);
        auto captionLabelJP = new CaptionLabel(CONTENT_JP, this);

        auto bodyLabel = new BodyLabel(CONTENT_EN, this);
        auto bodyLabelCN = new BodyLabel(CONTENT_CN, this);
        auto bodyLabelJP = new BodyLabel(CONTENT_JP, this);

        auto bodyStrongLabel = new BodyStrongLabel(CONTENT_EN, this);
        auto bodyStrongLabelCN = new BodyStrongLabel(CONTENT_CN, this);
        auto bodyStrongLabelJP = new BodyStrongLabel(CONTENT_JP, this);

        auto subTitleLabel = new SubTitleLabel(CONTENT_EN, this);
        auto subTitleLabelCN = new SubTitleLabel(CONTENT_CN, this);
        auto subTitleLabelJP = new SubTitleLabel(CONTENT_JP, this);

        auto titleLabel = new TitleLabel(CONTENT_EN, this);
        auto titleLabelCN = new TitleLabel(CONTENT_CN, this);
        auto titleLabelJP = new TitleLabel(CONTENT_JP, this);

        auto titleLargeLabel = new TitleLargeLabel(CONTENT_EN, this);
        auto titleLargeLabelCN = new TitleLargeLabel(CONTENT_CN, this);
        auto titleLargeLabelJP = new TitleLargeLabel(CONTENT_JP, this);

        auto displayLabel = new DisplayLabel(CONTENT_EN, this);
        auto displayLabelCN = new DisplayLabel(CONTENT_CN, this);
        auto displayLabelJP = new DisplayLabel(CONTENT_JP, this);

        // Create layout
        auto mainLayout = new QVBoxLayout(this);
        mainLayout->setAlignment(Qt::AlignTop);

        // Add widgets to layout
        mainLayout->addWidget(captionLabel);
        mainLayout->addWidget(captionLabelCN);
        mainLayout->addWidget(captionLabelJP);
        mainLayout->addSpacing(20);

        mainLayout->addWidget(bodyLabel);
        mainLayout->addWidget(bodyLabelCN);
        mainLayout->addWidget(bodyLabelJP);
        mainLayout->addSpacing(20);

        mainLayout->addWidget(bodyStrongLabel);
        mainLayout->addWidget(bodyStrongLabelCN);
        mainLayout->addWidget(bodyStrongLabelJP);
        mainLayout->addSpacing(20);

        mainLayout->addWidget(subTitleLabel);
        mainLayout->addWidget(subTitleLabelCN);
        mainLayout->addWidget(subTitleLabelJP);
        mainLayout->addSpacing(20);

        mainLayout->addWidget(titleLabel);
        mainLayout->addWidget(titleLabelCN);
        mainLayout->addWidget(titleLabelJP);
        mainLayout->addSpacing(20);

        mainLayout->addWidget(titleLargeLabel);
        mainLayout->addWidget(titleLargeLabelCN);
        mainLayout->addWidget(titleLargeLabelJP);
        mainLayout->addSpacing(20);

        mainLayout->addWidget(displayLabel);
        mainLayout->addWidget(displayLabelCN);
        mainLayout->addWidget(displayLabelJP);
    }
};

int main(int argc, char *argv[]) {
    QApplication app(argc, argv);
    Win win;
    win.show();
    return app.exec();
}