[Maya -> xNormal] Normal Map Baking Artifacts

withered

Hey everyone,
after desperately googling consecutively for 2 weeks I still can't seem to fix my baking errors within xNormal with various meshes
I start off with modelling a LP, then do the UVs, duplicate the LP and add screws for details, combine the screws to the LP duplicate --> HP.
I tried creating cages within xNormal itself and by transforming vertices to encompass the LP mesh.
All of my edges are declarated as "hard edge", thus there should be no smooth/hard edge differences.
None of the mesh parts is smoothed.
The UVs are not distorted, I even unstacked my stacked UV shells.
I triangulated my mesh before exporting it to xNormal and used .fbx files.
Not even in Maya my bake worked out (see above).

See xNormal results above.
https://we.tl/qSfiTIqAdw
I uploaded a .7z file of my LP, HP .fbx files

best regards,
Marlis

CompanionCube

i'm noticing a lot of overlapping geometry and overlapping UVs on both Low and High poly.

withered

I merged the LP and HP meshes into one due to the fact, that I want to use 1 shader for all of the night table's parts.
Within the goal platform, UE4, it's supposed to be imported as separate mesh parts, as we are aiming to utilize it as a destructible mesh.-
Also the drawers can be opened and looted. I had to model faces that would normally not be seen therefor.
Is this why the bake is coming out so badly?