According to the search results, the main difference between Chandrayaan-2 and Chandrayaan-3 is that the former had an orbiter, a lander, and a rover, while the latter only has a lander and a rover. Additionally, Chandrayaan-3 has been designed with a "failure-based" approach, meaning that it has been designed to deal with potential failure scenarios to ensure a successful landing. Another difference is that the lander and rover on Chandrayaan-3 will be able to operate more independently, as there will be no human intervention possible once they land. Finally, the apparatus on the orbiters is different, with Chandrayaan-2 carrying nine instruments while Chandrayaan-3 will have a lone in-situ instrument called Spectro-polarimetry of habitable planet Earth.