The East Prussians and nostalgics are thankfully completely irrelevant nowadays. The exilees dying out and the 1975 accord between Poland and West Germany (East Germany did it in like 1950) confirming the Oder-Neiße border killed off their influence, which they mostly held on the conservative CDU and CSU.

The Preußische Allgemeine Zeitung (a chud newspaper founded by them) has less readers than even the communist newspaper Junge Welt and supporters of their political positions are fringe even in the CDU/CSU and even AfD.

Maybe that'll change for the worse when Friedrich Merz of the CDU, an arch-neoliberal Black Rock employee wins the next elections, as I fear he will, but for now Germany does not have many cranks wanting back the borders of 1937 outside of the small far-right parties.