yes UE4 does use fbx(it can also use obj), blender has 2 fbx exporters you can choose from (“fbx 6.1 ASCII” or “fbx 7.4 binary”), using the old 6.1 version often fixes issues like the one you have.
also I have no issues getting animations from blender to UE4, the people that say it’s impossible just haven’t got the workflow right yet.