Like Russian Whites. And Republican Spain. Really, that's not unrealistic.
To be blunt, those are not even remotely comparable. Nazi Germany is neither Spain in the '30s nor Russia from 1918-1922.
Republican Spain was the legitimate government of Spain, run by the Popular Front...which was still significantly less heterogenous than 'People's Germany'. And Russia was in a civil war after the Bolsheviks toppled the already unstable provisional government. And the Whites were largely led by established ex-Czarist generals.
The opposition to the Nazi regime was so weak that the 20 July coup plotters (who were mostly authoritarian, nationalist conservatives) had to stage a Bavarian fire drill....because most of the German population and the military supported the regime and viewed it as the legitimate government. And those who didn't like it were largely resigned to it and just hoped the war would end. And that was when it was quite clear that Nazi Germany was losing and that the 'Gröfaz' was leading the nation to ruin.
Never mind the fact that People's Germany is a really silly name, especially if you translate it into German. The available leaders also make very little sense. Adenauer was opposed to the Nazis, but refused efforts from the conservative resistance to recruit him because he viewed their plans as doomed to failure. He's definitely not joining a confused rebellion with Stalinists in it.
Mielke was just a Rotfront thug during the Weimar Republic and had to flee to the Soviet Union...so he'd probably still be in Russia somewhere. Otto Strasser had become a complete nobody even before Hitler came to power, and had to go into exile, where he remained a nonentity. Willi Stoph was a communist party member in the '30s, and then just a random Wehrmacht grunt until Germany's OTL defeat. Bertha Thalheimer was deported to a concentration camp in 1943, and would've probably died there, given her age and poor health.