I think that it could be useful for you to read the book "Prayer (Salat), According to the Five Islamic Schools of Law", in particular the section concerning Maghrib since it analyzes the various opinions in details: https://www.al-islam.org/shiite-encyclopedia/prayer-salat-according-five-islamic-schools-law-part-1#time-maghrib-and-%E2%80%98isha%E2%80%99-prayers