Formamidinium lead iodide (FAPbI3) perovskite has recently gained immense interests as a possible absorber of hybrid halide perovskite (HHP) based solar cells and are extensively investigated both on experimental and theoretical fronts. However, it is unstable against the moisture, making this material domain inappropriate for long run. The compositional engineering i. e., doping in the absorber layer (FAPbI3) of HHP solar cells appears to be very significant for enhancing the stability and overall photovoltaic performance of perovskite solar cells (PSCs). We deal with the numerical simulation and optimization of (GA/FA/Cs)PbI3 based PSC. A diverse set of ETLs and HTLs have been explored to find the optimal combination from 35 device structures. Among them, La‐doped BaSnO3 (LBSO) and CBTS are found to be most appropriate electron/hole transport layers (ETL/HTL) combination for (GA/FA/Cs)PbI3 absorber layer, respectively. In addition, the impact of various parameters such as thickness, defect density, working temperature and back contact work function on the overall device performance have been investigated. After comprehensive optimizations, the proposed PSC demonstrated the superior photovoltaic performance with power conversion efficiency of 24.36 % and fill factor (FF) of 80.17 %. The present simulation work can serve as a benchmark for the fabrication of proposed PSCs.