In Italy Germany is Germania, but Germans are tedeschi and German (the language) is also tedesco. (BTW, we lowercase people and languages and weekdays and months, but this is changing - English leads.)

The reason seems to be the Latin word theodiscus from Old German theod / people.

It is true. Here's a map of what Germany is called by other countries in Europe: https://jakubmarian.com/wp-content/uploads/2016/08/germany-e...

Interesting that Finland/Estonia call them, essentially, Saxony.

The Latvian/Lithunian name for Germany is the only one I don't understand. Does anyone know?

Similarly, the word "barbarian" comes from the ancient Greeks describing the people who lived around them as sounding like they were saying "bar bar bar".

I only knew it from Hungarian, which I guess is a slavic enough language to compare: https://en.wikipedia.org/wiki/N%C3%A9meth:

In Hungarian, német means "German" (the word has Slavic origin, literally meaning "he does not speak", since German is not a Slavic language)