But as the sun light are rotating, faces of the pyramid semi-aligned to the light have the same problem. If the acne appears in a cube at 12:00, in a pyramid appears at 11:00 and 13:00, for example.
I have testing with bias and when the light is perpendicular to the floor, you can use higher values. The typical shadow offset are less noticeable with this angle. So you can “torear” this (but not solve it completly).