Summary: Through SCAPS-1D simulations, this work designed an optimized FAMASnGeI₃/MASnBr₃ double-absorber PSC with 34.70% PCE, featuring 150/225 nm absorber thicknesses, minimized defect densities (10¹³-10⁹ cm⁻³), and ideal charge transport layers (10 nm TiO₂/150 nm NiO). Key achievements include exceptional Voc (1.3284 V) and FF (90.52%) through recombination suppression, with performance validated at 300 K. The study provides a complete theoretical blueprint for fabricating efficient, eco-friendly PSCs while identifying future research directions in stability and interface engineering.