In this work, a novel structure of all inorganic PSC (TCO/TiO2/CsGeI3/MoO3/Back Metal contact) has been numerically investigated and optimized. Initially, we simulated the structure by using different optoelectronic parameters found in literature that are substantiated theoretically and experimentally and obtained a PCE of 19.81%. After that, we have turned up a detailed analysis by varying the parameters including the thickness of the light-harvesting layer, ETL, and HTL, bulk defects and amphoteric defect of the light-harvesting layer, interfacial defects, operating temperature, series resistance, and work function to obtain optimum values. The efficiency as high as 22.85% has been achieved along with Voc = 1.16 Volt, Jsc = 23.97 mA/cm2, and FF = 82.25%, respectively for the optimized structure of PSC. We also investigated the capacitance-voltage (C-V) and Mott-Schottky (MS) plots for in depth understanding of the performance variation. The detailed analysis and optimized parameters of this study, we believe, will be useful in synthesising toxic element-free CsGeI3-based all-inorganic PSCs with higher efficiency and stability, paving the way for PSC commercialization.