Multi Mesh Armature from Blender to Unreal - Why is that so hard?

I have a object with multiple meshes (4 in this case - it’s an airplane mockup) and two problems.
The whole armature gets messed up when importing into Unreal except for one specific setting and I don’t know why - at the moment it’s trial and error.

But once imported I want to create a control rig, but the Rig-Gizmo separates from the mesh the further it gets pulled. What is wrong with my setup?

These meshes are all connected an armature renamed to root (importing in one piece would not work otherwise).

These are the export settings I’ve tried. Only one worked.

Unreal import settings:

As you can see, every armature is messed up in one way or the other except for one.

This is the problem I have with the control rig. The further it gets moved, the more it separates itself.

Why is this?