This is how to create toolpaths for a corner radius endmill in Fusion 360.
Begin by making a fillet the proper size on the solid model you are trying to cut. The endmill radius must match the fillet radius on the model.
Select the bottom of the fillet with the 2D contour toolpath in Fusion.
I like to apply a few stepovers for harder materials. Aluminum isn't as much of an issue.