Techart, Blender, Geometry Node, Procedural, Programming.
FBX and nothing else, you can also bake the pivot into UVs. For Pivot baking in UVs, store them as two 2D vectors on the Face Corners. Then apply that modifier. You will see that you have two new UVs holding your pivot. This can be exported as FBX and imported into Unreal, Unity or Godot. There is