Addendum: Observational redshift from general spherically symmetric black holes Diego A. Martínez-Valera, Mehrab Momennia and Alfredo Herrera-Aguilar Eur. Phys. J. C, 85 4 (2025) 404 Published online: 10 April 2025 DOI: 10.1140/epjc/s10052-025-14114-z