When I import objects as OBJ + MTL or FBX, the colors are wildly different from the ones I see in Blender, Anything below 70% brightness is near black and everything above 80% is almost pure white, it seems Cospaces has a very low Dynamic range, are there any settings I can tweak?
This video should be the solution to the issue you’re experiencing 
https://www.youtube.com/watch?v=qZvia8IBXGE&t=360s
(the video will start playing at the part that’s relevant to models not appearing as they should when imported from Blender)
Hope this helps but please do let us know if you still find yourself encountering any problems.