In this work we study the impact of doping with Mg and Sc on P2-Na0.67Ni0.33Mn0.67O2. Through a combination of resonant inelastic X-ray scattering (RIXS), operando X-Ray diffraction, X-ray absorption spectroscopy (XAS), X-ray pair distribution function analysis (PDF), and density functional theory (DFT), we found that while Mg and Sc can both decrease the oxygen activity shows irreversible structural changes. These results were surprising at first because they point towards redox behavior being more critical than structural changes for improved cycle life in these materials. To further understand the role of Mg in suppressing the oxygen redox activity, we varied the amount of Mg doping and found that there exists a competition between Ni and Mg for triggering oxygen redox in Na0.67MgxNi0.33-xMn0.67O2 which is therefore dependent on the molar ratio of Mg/Ni.