No, it is not accurate to say that the electromagnetic (EM) waves produced by the displacement of a photon are more like a cone but are represented as 2D oscillations for mathematical purposes.
Electromagnetic waves, including photons, are not fundamentally two-dimensional oscillations represented for mathematical convenience. EM waves are three-dimensional oscillations in electric and magnetic fields that propagate through space.
An electromagnetic wave consists of oscillating electric and magnetic fields that are perpendicular to each other and perpendicular to the direction of wave propagation. This arrangement is known as transverse waves. The electric and magnetic fields oscillate in planes perpendicular to the direction of propagation, creating a three-dimensional pattern.
While it is common to represent electromagnetic waves as two-dimensional oscillations on paper or in diagrams to aid visualization and mathematical analysis, it is important to remember that these waves exist in three-dimensional space. The representation as 2D oscillations is a simplification for conceptual understanding and mathematical calculations, but the actual EM waves are three-dimensional in nature.
So, rather than thinking of the EM waves produced by a photon's displacement as a cone, it is more accurate to visualize them as propagating waves with electric and magnetic field components oscillating perpendicular to each other and perpendicular to the direction of wave travel.