Okay, so basically I got a huge industrial machine with complex and deep hierarchy in blender. The Empties within my hierarchy will later be animated with Timeline in Unity. I tried different things for exporting and importing but nothing really helped me. Most Forum Posts I read about don't adress Objects with a lot of nested Children. The following Lines try to describe some of my attempts of solving the problem but none of this actually did.
There is a Ticket where it's stated, that it is a known limitation for the Experimental Apply Transform Option https://developer.blender.org/T50405
I also tried the Rotation Fix for Unity (basically the 90° "Hack" you could do manually as well) https://forum.unity.com/threads/blender-unity-rotation-fix.181870/
I work with blender for quite a time now but never really had the need of such complex hierarchies. Any Suggestions? Maybe the only option is to export dozens of single components to prevent a deep hierarchy and compose the whole machine in unity out of several FBX files? So am I missing something big or is there really no viable workflow after all these years of unity and blender to bring a complex object to unity in one piece without messing up rotations?
Here are the .fbx files with the different Cases https://we.tl/t-GtoZXBIIAO