Cesium-based inorganic perovskites are promising alternatives to silicon solar cells due to their stability, tunable bandgap, and efficient light absorption. Unlike organic-inorganic hybrids, CsBX3 (B = Pb, Sn; X = I, Cl, Br) materials resist moisture and heat better. Within perovskite solar cells (PSCs), carbon-based electrodes such as carbon nanotubes (CNTs) and graphene, stand out for their low cost and long-term stability. In this study, SCAPS-1D software was applied to simulate and analyze the behaviour of CsBX3-based PSCs incorporating CNT as the back electrode. The investigation focused on four different PSCs with Cs-based absorber layers viz. CsPbI3, CsPbBr3, CsSnI3, and CsSnBr3. The optimized device architecture consisted of FTO/SnO2/CsBX3/CNT layers with specific thicknesses. Based on our simulations, the best cell came out to be CsSnI3, which had an impressive power conversion efficiency (PCE) of more than 25% and a fill factor of above 76%. This study shows that the performance of the device with CNT is similar to that of with gold electrode because the CNT layer serves multifunctional both as the hole transport layer (HTL) and back electrode. These results are expected to open new avenues for the development of incredibly stable and effective PSCs by offering researchers and industry professionals insightful theoretical information.