MULTIPLY-6G is a 36-month pan-European project working to redefine the core architecture of future wireless communication. By shifting beyond traditional signal processing into multi-dimensional waveforms and intelligent, extra-large antenna arrays, the project addresses the critical energy bottlenecks of expanding mobile infrastructure. Operating within an open, AI-native Open RAN (O-RAN) framework, MULTIPLY-6G aims to deliver a 100x leap in network energy efficiency while ensuring hyper-reliable, ultra-low-latency connectivity for a sustainable digital future.