Howdy Hitpawz,
So essentially what you want to do is get the Max Roughness, set within your Post Process Settings to a low value to increase the intensity of the specular highlights of your materials in your scene/level.
Here is an example of how I went about doing this within the Level Blueprint and changing the option while pressing the ‘R’ key.
Set Max Roughness for Post Process Volume
If you have further questions or need additional assistance, please let me know.
Cheers,