We are talking about a collapse of the most evil regime ever here. The victory can't be The Man in the High Castle-total either, or it would be ASB. So let's assume the USSR still exists beyond Ekaterinburg, and Europe is puppetised. The German Reich goes from Eupen to Ekaterinburg (including the Reichskommissariate) and has puppets in Hungary, Slovakia, Romania, Denmark, Norway, Finland, France.
And this collapses in a civil war. We are talking a vast Syria here, with the US and UK und USSR supporting amicable rebel factions, and after the civil war, Germany will be nonexistant probably.
I would suspect: All Reichskommissariate break away and apart, probably with the help of the USSR. These states become nationalist-communist, i.e. pro forma communist, but in reality radically anti-German.
Poland is created. Here it depends: If the Polish rebels are communist (mostly), it will become nearly OTL People's Republic of Poland. If the Polish rebels are democratic, it might become democratic and neutral. And if the rebels in Poland are fascists, (part of?) the Intermarium Federation might be created against the will of the USSR.
Hungary, Romania and Slovakia break away. Their course depends on the people more to the east... Free France will come back to Metropolitan France, Belgium and the Netherlands are reestablished.
And the real German Reich will not exist any more either, this will turn into a giant Syria with support from every side; there might be such states as Hannover, Schleswig, Prussia, Brandenburg, Saxony,... and I also predict some Nazi "rump state", or at least heavy guerilla fighting, in Bavaria and Austria's Alps.
The problem is will there even be a Poland to rebel? I mean, if we're talking even a cease-fire (as opposed to a full blown settlement), than the Nazi's are gonna jump on the Generalplan Ost train and they're not stopping till Poland is a country-wide recreating of the antebellum South.
As for the OP, it's very, very, very (did I mention very?) hard for the Third Reich to eke out a win that doesn't end with them getting rolled over by the UK/US in the 50's. If the remarkably unlikely event that doesn't happen, the resulting collapse is gonna be bad. Like, Syria meets Civil War-era China on meth bad.
but I still doubt they could be implemented so fully in 8 years that there would be no single Pole left.
Assuming the Nazis have had this area for 20 plus years, you're going to find that the bulk of the non-Aryan population has been severely reduced. The remnants are enslaved, and illiterate with their language and culture being eradicated. While the "satellites" might break away, there won't ever be a Poland. The German borders will be from the Rhine to wherever the boundary is between them & rump USSR or its successor state(s). This is assuming there is no war that destroys Germany but just the Nazi system falls apart on its own.
Communist China.
In my opinion, (long-standing) victory of the Reich implies:
- A defeated USSR will mean an anticipated death of the communism. So no communist China, no communism elsewhere (probably). A mostly Asian Russia would survive as a declining power, and maybe drifts into some kind of fascism too.
- The area directly ruled by Berlin (most of continental Europe) will be quickly Germanized, so national differences will be greatly reduced, if no totally erased.
- This regime might be internationally isolated, so it should be mostly autocratic.
I guess that, as every regime in the History, it will decline sooner or later. I think it will come relatively soon. One of the main 'problems' of Nazism as ideology (talking about ideology in sensu-stricto, not the horrible application of it) is that its own success establishes per se its sentence of death. Nazism was mainly based upon grievances, humiliations, retaliations, lebensraum, revenge against the allies etc etc. Once all these grievances have been paid by defeated and humiliated allies, once the German people has achieved its 'lebensraum', once all these perspectives have been accomplished...why to keep Nazism? At this point people would want freedom and good standards of live, both difficult to achieve in such regime, so different social conflicts will pop up quickly.
However, the fall of Nazism does not imply that Great Germany will balkanize (why? if there are not minor nationalities inside) or that the new regime will be democratic (it could be some kind of 'light' authoritarian regime).
I can see the Nazis doubling down on the evil after Hitler dies, leaving the reich in one massive graveyard. Snake Featherstone once noted about how the Nazis planned to have a national holiday revelling in the Holocaust.
I think that our descendants, 1000 years in the future, will think that we exaggerated the Nazis, because that level of evil seems almost impossible.
But yeah, it depends on who takes over after Hitler. If it's Himmler or Goebbels, than Europe is fucked.
Wrt China, the communists were well on their way to victory without Soviet aid by 1945. The kmt was just that screwed. That said, I can easily see Chinese backed communist movements in Europe arising
Once all these grievances have been paid by defeated and humiliated allies, once the German people has achieved its 'lebensraum', once all these perspectives have been accomplished...why to keep Nazism? At this point people would want freedom and good standards of live, both difficult to achieve in such regime, so different social conflicts will pop up quickly.
The KMT only lost because they moved to quickly to take over Manchuria after the Soviets withdrew, and the Soviets had left the Communists in place to take control of the area before the KMT got in. So when they actually did attack the KMT forces were too thinly spread to hold.
However, before the Japanese attacked the Communists were almost destroyed. Without Soviet aid, which isn't coming through TTL, and with the Americans having to move in to break the Japanese in mainland China (because the army may not surrender) the KMT is probably going to win.