> Even if hard right AFD would get the majority of votes in the next election, during one legislative term they could not change the system a lot. To do this, even the absurd long Merkle reign was not long enough.
This is a widespread misunderstanding. The AfD could drastically change the system if it had the sufficient number of seats (or a willing partner). There are very different pathways depending on what your goal is. Merkel was a conservative who had no interest in "changing the system a lot" (quite the opposite). The AfD wants to drastically change things like the immigration system.
It's a bit like how in the US the SCOTUS, thanks to the Trump appointed judges, effectively ruled that the President has a lot more power and is largely above the law (more so than these things already used to be the case before) but the Dems and Biden think the ruling is bad and thus refuse to do anything with that. They could also easily change the tune of the SCOTUS by appointing more judges but refuse to do so to avoid setting a precedent (as if the GOP needed it). "Centrists" often value decorum above succeeding at their stated goals.
There's an episode of Die Anstalt that plays through how the AfD could functionally abolish most of the constitution and democratic system within a single term if you want to know the specifics but it mostly comes down to abusing rules that exist because the system was created under the assumption that everyone would play fair (which is ironic given how things like the 5% hurdle are justified).
> There is a joke, that claim that the German anthem actually is:“ Stability, stability über alles“
I'm not sure where you heard that joke or whether this is a translation of the joke but the German anthem does not actually contain the words "über alles". The German national anthem consists of a single stanza of the Das Lied der Deutschen, the first stanza of which begins with "Deutschland, Deutschland über alles".
BTW it's a common misunderstanding that the "über alles" ("above all") part is why only the final stanza was used by West Germany for its anthem. However that was originally meant as an appeal to German nationhood and unification "above" the monarchs although it was later adapted as an expression of national superiority. The actually problematic part comes later in the first stanza where it names rivers as boundaries - not only did that include East Germany (a separate country) but also parts that were no longer part of either of the two countries.
As for why the second stanza didn't make the cut, I guess it was just a weird one to start a national anthem with as it celebrates German women, fidelity, wine and song and their "old respected fame" which at this point probably felt anachronistic and also wasn't as strong as the third stanza's "unity and justice and freedom" (with "unity" also having a new meaning when East Germany had become a separate country). That said, personally as a German I think it's a terrible anthem, especially given the melody was originally written to celebrate the Kaiser (first of the Holy Roman Empire and later of Austria-Hungary).
Personally I would have preferred the original East German anthem Auferstanden aus Ruinen, at least textually. It's also not great but at least it's better than digging through scraps to adapt an outdated poem set to a monarchist hymn.