you can't mitigate it with the raise ground tool, - other than just raising your entire base off the ground above the height of sea level.

the terrain is hardlocked to a max height and min height that is determined by the generated heightmap.

this means you can only dig down a set amount of blocks ANYWHERE no matter what until you reach the bottom.

you can actually dig out an entire patch of terrain until you can't dig anymore, and notice that the bottom layer where you cannot dig anymore is also the same shape as the original terrain, this is because the terrain heights are generated, and then it adds layers on top of it.

that means that no matter what, you cannot mitigate waves, because as others have stated, it is not something based on terrain, it is a set level.

which means in areas where the water is deeper by default terrain, the waves will push higher, and there is no amount of terrain manipulation that will change that.

you just have to move your base more inland.

take note that water also has tides in this game, i myself have built docks foolishly during low tide only to drown when the tide comes in.