This review in 2015 outlines the cellular physiology of each form of B12 and where each form is stored, as well as the potential therapeutic action of each.
Thakkar, K. and Billa, G. Treatment of vitamin B12 deficiency-Methylcobalamine? Cyancobalamine? Hydroxocobalamin?—clearing the confusion European Journal of Clinical Nutrition (2015) 69, 1–2. https://pubmed.ncbi.nlm.nih.gov/25117994/