The spotlights in my office are far too sharp. This small clip in diffuser softens the light but still keeps the room bright. 

The dimension of my particular lights are 51.3mm in diameter. The blender model is provided if the size needs to be adjusted. The diffuser is 8mm in depth, you can tweak this if needed to let in more or less light as desired. 

In Blender: 

The model has 2 cutouts provided by a boolean operation. You can tweak and change these as needed. The blender version is 4.2.3 LTS.