Russia is taking defensive actions, not because it thinks Finland wants to take territory from Russia, but because Finland has invited the U.S. to set up bases right on Russia's borders, and very close to one of its major cities, Saint Petersburg.

How do you think the U.S.A. would react if Canada or Mexico joined a military alliance with Russia and invited Russia to set up bases along its borders ?

And I'm aware of 'Finlandization'. That was still a beneficial relationship for Finland (back when Finland still had diplomatic skill & wisdom) but of course I note that you are conflating the Soviet Union with Russia. We are talking about Russia, not the defunct Soviet Union. Finland has enjoyed friendly relations for decades (since 1991) with Russia, without any 'Finlandization'.