A family member of mine taught ESL kindergarten in Finland for a year, decades back. She said Finnish is a difficult language to learn as an adult, and it doesn’t have any relation to the languages of its Scandinavian neighbors. In fact, it’s closer to Hungarian in terms of language families.
Finnish is a Uralic language with a very short “tree”. Finns and Estonians can mostly understand each other, for example. That said, Finnish is a fairly logical language with a straightforward grammatical structure.