P–R relations for O24_ML4h_RA models (f_H = 0.02, f_env = 0.04, η_R = 0.4) and the highest initial rotation rate of W₀ = 0.65, for MW, LMC, and SMC metallicities (Z = 0.014, 0.006, and 0.002 in the left, middle, and right panels, respectively), confronted with determinations from B. Trahin et al. (2021), W. P. Gieren et al. (1998, 1999), A. Gallenne et al. (2017), and P. Wielgórski et al. (2026, in preparation). In the first panel, we also display the P–R relation from M. C. Bailleul et al. (2026) based on interferometric observations of seven MW Cepheids (dotted gray line).