First of all, always check if the model's normal surfaces are facing at the correct direction.
Troubleshooting Bi-Normals Error (left):
cause: bad UV
Link that could help:
https://www.youtube.com/watch?v=Vz8Ne5perio
!!!!Mixed shader in Blender DOES NOT apply to the model when exporting as FBX!!!!
Reworked the entire material of Kassadin Sword on UE, will simplify material if required (performance)
Comparison between old(left) version on Blender and new(right) version in UE. Yes I do sometimes prefer the style on the left but hey it is what it is. The new version kind of gives us the "pre-rework Kassadin" vibe. (Will post the nodes later, and do an in-depth walkthrough)
Uncheck this circled option when exporting (under animation)
scale the rig to 100 in Blender then apply. then scale it back down to 0.01
don't use the default Blender metarig name.
setup a root bone