I was having the same issue on Cura 4.0 on both the longboat and the Dhow. Since PS uses Prusa printers to test their stuff I figured they might use PrusaSlicer as well so I’m currently running a test on the longboat to see if there is a noticeable difference. The only changes I made were to adjust a few things like infill and the like. Mostly I left everything on default settings.
The biggest thing I’ve noticed is that the Slic3r default settings keep the fan cooling on auto which only makes the fan kick on when it’s printing a lot of filament very quickly in a small confined space, otherwise the cooling fan is NOT on. So far, it looks like the quality is better on Slic3r than on my best Cura settings. I’m wondering if keeping the fan off is allowing the filament to meld better to the sides of the ship. I’m not entirely sure why that would be but its the best theory I have right now.