CSG on meshes isn't really where FreeCAD struggles or focuses. That's more BRep, which is a harder problem than CSG.

Blender used to struggle with boolean operations, though. Seems to have got much better some time in the last couple of years, but without knowing any of the backstory I don't know if they've bodged it into shape or would benefit from something proven.

I think this would need to be reimplemented for performance. But maybe the spec can be reused. As agents get better we might reimplement the same spec for performance with minimal human effort. (See notes regarding performance and floats in readme.)

Does FreeCAD use triangle meshes? CAD is usually NURBS surfaces, which require similar algorithms but on curved surfaces.