I wanted to show an example of something that would help solve the fillet/chamfer boundary issue but then ran into one myself.

The basic premise is to build your own radius fillet or chamfer, and in a simplistic sense I was about to do this when I ran into a trim issue. Using a project curve to remove surface material, the results are odd where it won't completely trim the surfaces I want removed 'inside' the projected curve.

I didn't try this as a surface, considering instead a trim curve is cleaner methodology: