Palestine

Hell, one can consider the US the original genocide-reich. The previous European imperial projects before had been horrendous and genocidal, yes, but genocide (outside of cultural genocide) had not exactly been the intent (but rather ruling over, and literally exploiting the natives to death).

The US was the first great genocidal settler-regime, and the ever-expanding success of its genocidal settler policy convinced its progenitor (Britain) and the rest of the west to follow in its footsteps; the Nazis themselves were directly inspired by Manifest Destiny (and the romanticization of taming the "wild west" in the works of Karl May), and explicitly attributed this inspiration multiple times by prominent leaders, for instance in Hitler's Mein Kampf.

It's not a coincidence that when Churchill also referenced first the indigenous peoples when he spoke deriding the Palestinians as "dogs" who don't deserve their homeland- in his exact words,

"I do not agree that the dog in a manger has the final right to the manger even though he may have lain there for a very long time. I do not admit that right. I do not admit for instance, that a great wrong has been done to the Red Indians of America or the black people of Australia. I do not admit that a wrong has been done to these people by the fact that a stronger race, a higher-grade race, a more worldly wise race to put it that way, has come in and taken their place."

The US is not the 4th reich. The US is the Great Reich, the first western state to wholly and utterly embrace genocide in its entirety and as its reason for existence, and from which spawned many pale imitators, and also in many ways the purest form of the genocide-state, a nation which has not one inch of land it did not steal and dispossess the natives of, not one inch of land which is not an ongoing site of lowkey, silent genocide- and a nation which has fought against indigenous peoples wherever they exist, backing fascists, or other times instigating tribalist divisions and extremists, etc...