I think you might be mixing different things here, because it’s fucked up shit

Northern Europe: British isles, Scandinavia, Finland, Baltics

Nordics: Finland, Sweden, Denmark, Norway, Greenland, Iceland, Faraoe islands

Scandinavia: Sweden, Norway, Denmark

Scandinavian peninsula: Sweden, Norway, North-western Finland

Fennoscandia: Finland, Sweden, Norway, Murmansk oblast, parts of Karelia and Leningrad oblasts

And there’s more stupid definitions for differently divided areas because fuck you

Finland and baltics are northern Europe, not eastern.