Meaning 'not only... but also'. Expresses that both Nouns are true or notable, but the second is particularly emphasized.
The grammar point 'Noun もさることながら Noun も' is used to express that both Nouns are true, important or relevant. It can be translated as 'not only... but also' in English. However, among the two nouns, the one coming after 'もさることながら' is emphasized more in comparison to the one before it.