Nonlinear field-grading materials (NFGM) control the electric stress in cable accessories by adjusting their conductivity dependent on the local electric field strength. In high-voltage DC cable joints, NFGM might be incorporated as a grading layer between the cable insulation and the cable joint insulation, achieving an electrical decoupling. This introduces a second interface between the cable insulation and the joint insulation, complicating the manufacturing process of the cable joints and potentially introducing additional fault locations. For medium-voltage DC (MVDC) cable joints, it could be beneficial to incorporate the specifically tailored NFGM directly into the insulation of the cable joint, thus reducing the complexity of the insulation system. The aim of this publication is to assess the performance of different field-grading techniques by conducting a case study using thermo-electric finite-element modeling. Two algorithms for developing target material properties are compared.