Is there a south-up setting for a projection in QGIS?
If you set the project CRS to a south-up projection like
EPSG:22281 Cape / Lo21, you will get a map with the South pole upwards:
Note that common raster basemaps like Openstreetmap will have labels upside down as well with this projection, whereas labels of your vector data will appear in a readable orientation.
You can define a south-up CRS with
X is west,
Y is south,
Z is up.
It doesn't save that in the
prj file though. When you load a layer with this projection, you have to set the CRS in the layer properties. Other than that it works properly.