The scalable preparation of bosonic quantum states with macroscopic excitations poses a fundamental challenge in quantum technologies, limited by control complexity and photon-loss rates that severely constrain prior theoretical and experimental efforts to merely dozens of excitations per mode. Here, based on the duality of the quantum state evolution in Fock-state space and the optical wave-function propagation in a waveguide array, we introduce a Kerr-engineered multilens protocol in a single bosonic mode to deterministically generate Fock states exceeding 10, 000 photons. By optimizing phase and displacement operations across lens groups, our approach compensates for non-paraxial aberrations, achieving fidelities above 0.73 (0.61) in numerical simulations for photon numbers up to 10, 000 (100, 000). Counterintuitively, the protocol’s execution time scales as N [−][1][/][2] with the target photon number N, exhibiting robustness against the photon loss. Our framework enables exploration of quantum-to-classical transitions of giant Fock states, paving the way for advanced quantum metrology with significant quantum gains, and error-corrected quantum information processing in high-dimensional Hilbert spaces.