lighting – Unity Soft Shadows

I'm building a puzzle level in Unity. I have a bullet with cracks and a bright spot on the inside. The goal is to project light through the cracks in the walls.

I managed to do it but the lighting is not soft (it does not disperse on the surface, so it looks very neat). The walls are simple Unity cubes.

Soft shadows

I use soft shadows on the properties of light, but that does not seem to make any difference. I guess the shutter is so close to the light source that lighting becomes very sharp. Is there a way to control his sweetness?

I tried to play with the smoothness of the wall material, but that has not changed.

I've also tried to turn the cracks into an alpha channel albedo map (with zero or near zero alpha values ​​where I wanted the cracks) and give the ball a perfect sphere instead of the mesh of the bullet having physical cracks. Although it works with the cut mode, it gives me the same result as before. Another thing I tried was to put it in transparent mode, but the transparent shadows are terrible! Is there a way to improve their quality?

I searched for Soft Shadow assets (free) for bright spots, but I could not find any.

Is there a solution for this?

Thanks in advance!