And if this is the vaunted capital of the "Master race", then i think the situation in the East would be mmuch more chilling. Heck i can see entire cities resembling
Hashima Island
As interesting as Hashima is, I think its a relatively poor example. Hasima exists sorely due to a japanese shortfall of coal, hence its logical that a city would emerge inorder to extract one of the few rich sources of coal within Japan's territorial borders.
A victorious Reich is faced with a very different set of circumstances. They are trying to reenact hitler's vision of a lebensraum, by creating a German frontier for future colonization. European Russia was to be depopulated for the sake of largely agrarian German settlers. The economic problems of this are obvious. Agricultural is already becoming far less labor intensive, most German's lack the knowledge for farming the Ukrainian steppe, and the costs of wiping out the Slavic population while colonizing it with repatriated Germans would be astronomical.
Rather than a series of Hashima's, you would be left with centrally planned ghost cities. Meant for settler populations far larger than what emerged, they would be saddled with idle apartment blocks, uncompetitive light industry, and overbuilt infrastructure. While there intention would be to permanently bind the "Aryan" race to eastern Europe, they would be inhabited by a skeletal crew of colonists, administrators, soldiers, and subject peoples while the countryside is left in ruins.
That being said, you work corresponds to this perfectly. I'm mostly nitpicking.