Was there any real inkling after the first world war? A few people have said that there were already indications after the Vormärz and especially after the war with Prussia, but I've not been able to find anything on that.
Everything mostly seems to start after the 2nd world war and just treats it as a fact, already existing.
To me so far, it seems to be an identity built around the Opferthese/Victim Myth. I'm also aware of the Waldheim scandal, but I'm unsure how it fits in.
In many ways the aftermath of the 1st world war and the (much reduced) status of austria led to the desire to integrate with germany in the first place, because of concerns about the ability to survive and thrieve as a small nation.
Even then there was not a clear majority for integration and it was also not clearly cut among party lines (left-right). Of course with the exception of the (banned) austrian nazi party.
(Hugo Portisch Österreich I as well as the obvious Hopsbawm: Age of Extremes. The short twentieth century, 1914-1991)
Prior to german unification (which in the end was led by Prussia) there were always two options on the table Grossdeutsche (big-German, including and led by Austria) and Kleindeutsche (small-German, without it) solutions.
The German speaking minority within the Habsburg lands did no necessarily support the Grossdeutsche Lösung.
The "Vormärz" rebellion in Vienna was actually one of the few instances where the german-speaking austrians were moving in synch with the wider german speaking Lands (Deutsche Revolution von 1848/49) and even then, it started in support of a hungarian rebellion.
Hans-Ulrich Wehler: Deutsche Gesellschaftsgeschichte as well as another Hopbawm: The Age of Revolution: 1789–1848
After the second world war the Victim theory and and the assotiation with the habsburg monarchy (historical films boomed in the aftermath of the war) was a convenient way to forge an identity and disassotiate the Austrians from the Horrors of Nazi Germany (even though plenty participated in them).
The Waldheim affair was basically a rude reminder, and also started a process of rethinking of the Victim theory in Austria.
Even then, the Waldheim affair was also seen as a plot to undermine the clear favorite for the Office of President of Austria (largely ceremonial), when he had been secretary General of the UN beforehand and the accusations started surfacing while he was campagning. (no sources, this may narrowly violate the 20 year rule, ill delete when prompted)
In conclusion Austrian Identity is a complex thing.
Historically as well as psychologically.