terraindata.setheight as a brush for runtime terrain editing

my apologies if this has been awnsered before but i've spend 2 days searching with no results but i have made( i'll be honest and say that i copied it) a terrain editor that can be used during runtime by the player however whenever i use it it only raises the smallest of points since it works with a raycast shooting from my mouse

so my question is how do i make it raise a larger area of effect

  void raiseterrain(Vector3 point){
             int mousex = (int)((point.x / terndta.size.x)*heightmapwidth);
             int mousez = (int)((point.z / terndta.size.z)*heightmapheight);
     
             float[,] modifyheights = new float[1,1];
             float y = heights[mousex, mousez];
     
             y += strength * Time.deltaTime;
             if (y > terndta.size.y) {
                 y = terndta.size.y;
             }
     
             modifyheights[0,0] = y;
             heights[mousex,mousez] =y;
     
         
             terndta.SetHeights(mousex, mousez, modifyheights); //<---- this needs to become an area instead of a singular point
         }

once again my apologies if it has been asked before but i just cant seem to figure this out