I’ll give a short update on the latest state of this feature. In 2018, @Anthony_Divitto worked on a pull request to add this option as a display-only feature (so, Y values are displayed inverted, but the saved map is not affected):
The change wasn’t completed however, but a few months later was continued by AdrianFL, and in the end we had a clean patch, but it was never merged due to a problem with object alignment we noticed:
Since then, Tiled did gain an option for modifying the alignment of objects, though only for tile objects, and the option is set on the tileset. So this does not really help yet in this case. That said, the work done to support this may help to finish this feature.
Feel free to also let us know what exactly is the behavior you’re looking for, and whether reversing the alignment of the objects is indeed required for this option to be useful.