If I had so dimensions indications I could make something in Blender, for me it seems to be a U-form piece, kind of tube cut in halve, right?

In my last post I provided links with what I made. That includes a .sh3d file with the object of the corner. It's a shape created with the Shape tool, copied, the copy mirrored and rotated, and then the two parts attached to each other. So it's a weird shaped corner.

There's also a screenshot with the dimensions I used for the corner object. Maybe import the shape objects from the .sh3d file in Blender and go from there. A little thinner with smoother edges.