Recently, all-inorganic double perovskite, lead-free absorber-based perovskite solar cells (PSCs) have been an active area of research. Due to its narrow bandgap and wide and high absorption, Cs₂PtI₆-based PSCs have generated wide interest. In this work, a comprehensive study of a Cs₂PtI₆-based PSC using solar cell capacitance simulator (SCAPS) one-dimensional is conducted. The simulation result is validated by comparing it with experimentally reported Cs₂PtI₆-based PSCs. To design a highly efficient, commercially feasible PSC, the variation in the performance of the PSC with six different electron transport layers (ETLs), ten-hole transport layers (HTLs), and nine metal contacts is investigated by simulation. Among the tried configurations, FTO / ZnO / Cs₂PtI₆ / MoO₃ / Cu yielded the highest power conversion efficiency (PCE). The effect of varying the parameters of thickness, defect density, and doping concentration of the absorber layer; thickness, and doping concentration of the transport layers; and defect density of the interface layers on the performance of the device is investigated. The optimized device configuration yields an open-circuit voltage (Voc) of 1.3856 V, short-circuit current density (Jsc) of 16.107 mA / cm², fill factor (FF) of 75.54%, and PCE of 16.85%. When the simulation is done with different back metal contacts, carbon yielded encouraging results with a Voc of 1.4105 V, Jsc of 16.112 mA / cm², FF of 90.01%, and PCE of 20.45%.