an increasing number of people aren’t voting at all
That seems wrong. At least in Thuringia, Saxony and Saxony-Anhalt (the states mentioned in the paper) voter turnout has been quite stable the last 20 years.
A quick search leads to:
https://www.wahlen.sachsen.de/landtagswahl-historie-eckdaten.html
German here.
While we have real problems with the far right gaining ground in Germany I would argue that it is by no means comparable to the situation the US currently finds itself in.
I mean, the USA is literally one year away from the real possibility of full blown fascism while the fascists in Germany get 21-22% in polls and currently have no chance to successfully overthrow democracy.
So yes, I would argue that the USA is a couple of steps further than Germany along the way to fascism.