Align the normal of a face or set of faces to Global orientation
Download ZIP file on your system.
In Blender, install addon from Preferences > Add-ons > Install...
Activate the addon
Select the object to align to Global orientation. In mode Edition, select a face or a set of faces with the Normal correctly oriented.
Go back in Object mode then choose Object > Transform > Align to Global Orientation
In the panel to adjust last operation (F9), if your object has children, you can select Apply to Children to apply the rotation to them. Select Apply Recursive if to apply to children of children.