@NilsonLima You can make the argument of who ‘needs’ to do what. But if we look at which side of the divide involves the least amount of work to get a working solution. I think the choice would be on the Unreal Engine side of things rather than Blender.
FBX is a closed format, its official import sdk can not be incorporated into Blender. Everything on that side will always be guesstimates. Better to handle this with a custom Blender aware importer in Unreal Engine. Given how many people this effects and how much easier it would make development for smaller teams. Epic Games stands to gain a lot from providing this kind of support, it would be totally justifiable.