Roughness determines which parts of a mesh should be reflective - less rough means more reflections. Bring an interior or exterior(with more stuff than just a sky and clouds) HDR image into the engine instead of using that sky map and you’ll get a better result.
Here there is an HDRI in the post prcess and a spotlight, but as you can see the image reflections are more dominant.
Dont forget to set the skylight source type to Specified cubemap when you use and HDRI. Make sure the HDR image is in HDR format when you import(also, it will be downsized to 512 in game regardless of the size you import at.) And dont forget to use static lighting if you decide to use reclection spheres. Post your material setup if you still run into problems.