Also noteworthy are the different terms for "German" in different languages, they're quite far apart: "Deutsch", "Allemagne", "Nemți", which all derive from the names of different Germanic tribes. Depending on which tribes surrounding countries (which were faster to establish nation states) were closest to, that's what they called all Germans. And it stuck.
true-ish. I'm not aware of any tribes that would give name to Deutsch and Nemti. Rather, Deutsch is the generic self-description for all tribes, and Nemti was a generic description of all tribes by slavic people (ie Niemy in polish meaining "without the ability to speak")
I thought:
Deutsch: https://en.m.wikipedia.org/wiki/Teutons
Nemți: https://en.m.wikipedia.org/wiki/Nemetes
But at least Deutsch does indeed appear to have other origins according to: https://en.m.wiktionary.org/wiki/deutsch