The goal of the corner protector is to absorb impacts, distribute the forces and maybe buckle at bit but not collapse as a whole.
Print 8 of them and use double sided tape to fit them to all the corners of your shipping item (in my case a piece of HiFi equipment) before you bubble wrap it and put it in the shipping box.
Clas Ohlson PLA
I used Slic3r with 2 perimeters and 15% gyroid infill for it's uniform strength and I believe it's more tensile than cubic. You may use a raft or no raft depending on your print surface.
I used FreeCAD to design this