I am not sure what dangers you imply here.

America to the West, Africa to the South, Russia and China to the East. Constant tensions at the borders of Europe. To me the neighborhood looks incredibly dangerous and increasingly so. On that subject, the lackadaisical attitude of some EU nations towards defense is bewildering (looking at you Germany).

USA is basically surrounded by large oceans and they still spend by far the most on defence.

The US's military expansion (and by extension its defense budget) is directly correlated to its domestic industrial expansion and its need to keep supply lines flowing. They basically spend a lot because they need to jump over two oceans to afford the economic model they chose. That wasn't the case when the US was still content with self-isolation, before the Spanish–American War.

Switzerland used to be surrounded by Nazi Germany on pretty much all sides.

They remain independent because they are a mountainous country that set its defenses up cleverly so that any invasion would be a pyrrhic victory at best.

Most of the population lives in the flatter parts of Switzerland, which are of no real concern for invasions from the West and North. The linguistic border runs inside Switzerland because the geographic border does as well.

That is a myth. These defenses you talk about were built partly with cheap material and therefore significantly less effective. This caused a major post-war corruption scandal.

Nazi Germany did not invade Switzerland, because Switzerland was actually more useful as a neutral state for Nazi Germany to exchange gold for commodities, for spying and Switzerland produced militiary equipment for Nazi Germany anyway.

Switzerland has also had a policy of armed neutrality since 1815 or before I think and the armed bit would probably be a headache for anyone invading.

The Nazis did plan an invasion. See Operation Tannenbaum[0].

Switzerland didn't end up getting divided between Germany and Italy thanks to the Red Army hurtling more humans west than the Wehrmacht could supply bullets east. Swiss munitions production wouldn't be risked.

[0] https://en.wikipedia.org/wiki/Operation_Tannenbaum

There's this joke in Switzerland: When the war wasn't going so well Hitler sent a note to the Swiss government demanding a supply of tanks. The Swiss council deliberated and responded in due time: "Will one be enough or do you need all six?"