Even if the projection is assign, the QgsRasterLayer and the QgsRasterDataProvider was not updated. In the case of a layer loaded in the project a fix has been provided #37919 In the case of a layer ...

Winkel Tripel map projection is still blacklisted in GDAL. Since it is one of favorite map projections for world maps, with this custom install of GDAL one can use this map projection in QGIS or GRASS ...

For this you will need to have GDAL already installed. If you need to install it, then further details can be found at https://gdal.org. Open a terminal or command prompt and navigate to the folder ...