Delensing for precision cosmology: optimizing future CMB B-mode surveys to constrain r Wen-Zheng Chen, Yang Liu, Yi-Ming Wang and Hong Li Eur. Phys. J. C, 85 6 (2025) 702 Published online: 26 June 2025 DOI: 10.1140/epjc/s10052-025-14386-5