How to convert sJIS rom header to utf8 in qt6

I'm trying to help with simple64 which uses qt6 and displaying the sJIS rom header to utf8 correctly.

The SJIS Header is Japanese.

At the moment it's showing ������Ϻޯ�ܰ��� (sJIS) or this ÐÝÅÃÞÀϺޯÁÜ°ÙÄÞ (utf8) when I'm using a QByteArray to try and convert it.

The code currently uses this:

output = QString("%1: %2").arg((const char *) Context, message);

I know that %2 contains the string I need, unfortunately it just displays as a great big information dump.

I've tried doing this code in an attempt to split the strings so I can isolate the one in question:

void split(const QByteArray & a, QList<QByteArray> & l, int n)
{
    for (int i = 0; i < a.size(); i+= n)
    {
        l.push_back(a.mid(i, n));
    }
}

void DebugCallback(void *Context, int level, const char *message)
{
    if (level == M64MSG_INFO)
    {
        split(ba, ql, ba.length());
        
        for (QList<QByteArray>::const_iterator itl = ql.constBegin();
        itl != ql.constEnd(); ++itl)
        {
            const QByteArray & a = *itl;
            
            for(QByteArray::const_iterator ita = a.constBegin();
            ita != a.constEnd(); ++ita)
            {
                output += *ita;
            }
            
            output += "\n";
    }

What am I missing for the conversion? Also I don't want to use the qt5Compatibility as it adds more dlls just to solve this.

I'm semi-positive I could use the QLocale::language but i'm not sure on it's usage even after checking the documentation.

The conversion needs to work for any sJIS characters.