Perhaps I'll start.
As I said, it's a bit premature, because we're only in year one of this particular study, but I think it has to be a combination of both. As I said, the size of the wave depends on the speed and size of the ship, and also the distance from shore, along with all the other factors.
If ships can be regulated or encourage to move at certain speeds and distances that reduce the wave height, that makes sense to me, but I think also shorelines along rivers in general need some kind of stabilization if they're already eroding. Ideally it would be in a way that allows some naturalization so that natural river processes of sediment transport can continue—