It really doesn't. Just because the Germany Bormann builds is stagnant and crumbling doesn't mean that his death will instantaneously lead to the whole country imploding in on itself. Would there be civil strife and conflict? Certainly. But you don't just fucking invade a nuclear-armed country just because it's undergoing massive civil unrest.
I feel like a lot of people have misrepresented the 2WRW on this thread. How I remember the lore for it going is that Bormann kicks the bucket, the Second West Russian War starts with the USSR invading. The Russians make it to Moscow, where conflict starts to slow down. The Americans broker a peace agreement between the Germans and Soviets, and the resulting fallout of the war forces Germany into the American sphere, at which point it technically becomes a Republic (probably meaning that it cleans up its public image while not really democratizing significantly).
Even if the US didn't have blatantly self-serving interests in coercing the Russians into a disappointing peace, I say they would still have valid concerns about the post-Bormann government (who would be more cognizant about their detrimental position than anyone else in-universe) getting angsty enough and resorting to pulling the nuclear dead-man's switch. Enacting "De-Nazification" after this government transitions into OFN alignment is of course going to be a piecemeal effort due to the sad, simple fact that the ITTL window for anything like the Nuremberg trials and so has closed the moment lore magic made Germany a nuclear power and thus able to leverage MAD at anyone who has the ambition to take over Germany and dismantle Nazism's legacy effectively.
Now, what's left unsaid is how the other Eastern Reichkomissariats fit into the equation, post SWRW. I believe that- as an obvious matter of common-sense and to make the transition from Nazism more serious and stabilized for new OFN hegemony, the US would do away the structure of German over-lordship, and turn them into native-run OFN-aligned states. In the case of Poland, Norway, Netherlands etc, I suppose it is a matter of returning the governments-in-exile.
Stanning a weird, bad piece of lore that no longer applies to anything is certainly a choice, and I don't know why so many people are making it.
Because when you really think about it, it
makes sense. One of TNO's aims is to explore how the Axis victory of WW2 utterly changed world history (for the worse), so it would just break the immersion if, just like OTL, the Soviets just takeover the whole of Eastern Europe from the Nazis, hoist their flag over the Reichstag and then happy ever after. Even if we were to dismiss the aforementioned fact that the Germans have nukes and that any contenders for the top spot aren't going to be idle as the Russians go on a land-grabbing spree to their detriment. And I think you slightly overestimate how ruinous the post-Bormann environment would become.
The way I see it at least, as damaging as Bormann's purges were, it paradoxically also meant that there isn't any organised, opposing factions that are influential enough to try gunning for power. The turbulence that hits German society with his death would be more the weakened government struggling to get their house back in order, than yet another civil war.