So long ago, I asked on how to make Earth's oceans as brackish as Lyr's, one of the many worlds imagined by artist Chris Wayans. The only real answer I got was something that that world had already gotten covered--less land.
Simply speaking, the less land there is on the surface, the less rock there is to erode, and the less rock there is to erode, the less ions there are to be dumped into the oceans. That is how our oceans ended up being so salty.
So here is my map of an alternate Earth consisting of nothing but islands.
If any specifics help with the scaling, it is equal in mass, diameter and gravity to Venus. It has no axial tilt, which means no seasons. The highest point above sea level is barely twelve feet. Mathematically speaking, is the proportion between land and water presented in this map enough to make the oceans freshwater instead of salty?