You are correct about the chamfer and the radius being involved.
However,,,,,Mopar factory cranks are made with Undercut fillets ,,,,and don’t truly require the chamfer .
The chamfer also helps strengthen the rod caps and the rod journal area .
It helps to relieve a stress riser area by giving a blended radius to the journal so it doesn’t have a sharp edge to cause a fracture .
And I think at one time I read that the chamfer aids the oil buildup ( Dynamic Wedge ),,,,that helps them float the bearings ?
They still need the chamfer area,,,,but it will survive with a marginal chamfer as well .
Tommy