What if the East German socialist state that existed from around the end of the Allied occupation of Germany around the early 1950's till the fall of the Eastern Bloc around 1990 had, instead of claiming to be the legitimate government of all Germany (which resulted in tensions within European Cold War geopolitics), decided (or "decided") to form its own national identity separate from Bonn?
That's exactly what it did in OTL--especially under Honecker. (Ulbricht had perhaps never quite given up on the idea of some sort of German reunification.) It explicitly rejected the West German position that there were "two German states but one German nation." According to Honecker "All talk of the unity of the German nation" was "twaddle."
https://books.google.com/books?id=n8OvCwAAQBAJ&pg=PA203 There were two German nations, said Honecker, one capitalist, one socialist.
Abgrenzung--"demarcation"--between the GDR and the FRG was a constant theme of his. The GDR Constitution of 1974 made this explicit by dropping all mention of a single "German nation" which had figured in previous GDR constitutional documents.
https://books.google.com/books?id=hWZ4DQAAQBAJ&pg=PT524
Of course its separate national identity was based on ideology, but it was still a separate national identity. And in fact there was no plausible basis for anything other than ideology as the demarcation. The GDR could not identity itself with Prussia--it contained many lands that had never been part of Prussia (as well as of course lacking many that were.) In particular, many Saxons were prominent in the GDR--Ulbricht was notorious for his Leipzig accent.
https://books.google.com/books?id=H-neBAAAQBAJ&pg=PA142
It was the FRG, not the GDR, that had a Federal Minister of All-German Affairs, later Federal Minister of Intra-German Relations.
https://en.wikipedia.org/wiki/Minister_of_Intra-German_Relations To the GDR, at least under Honecker, the FRG was a separate nation with a separate social system. The GDR had diplomatic relations with the FRG exactly as it had such relations with France, the UK, or other capitalist nations. (Such at least was the official theory, even though ordinary citizens of the GDR probably did not regard the FRG as a "foreign" nation in the sense that France was.)
I get the weird felling that this forum contains a lot of DBWI's that are not identified as such...