I am planning to do a run wherein I will get the achievement 'An Early Reich', and seeing that Austria appears to be in the best starting position in the Germanic region of Europe, I an curious if that country would be the best candidate to unite Germany, excluding other prince-electors within the region that is.
Here is the wiki article about Germany - https://eu4.paradoxwikis.com/Germany
You would have to lose the position of the Holy Roman Emperor and switch your culture from Austrian to some other German. I wouldn't call it the easiest route. I suggest instead taking Brandenburg. Another interesting option is Teutonic order on condition that you join HRE ASAP.