I'd like to see this carried out by a pre-WWI, alternate WWI (different alliances), or alternate (smaller-scale, no Hitler) WWII Germany (I can't support Germany winning WWI, being a Frenchman). Before Naziism, Germany was actually one of the kindest European states towards the Jews. Because Yiddish was so close to German, the Germans tried to recruit Jews into their ranks in the census to increase the number of German-language schools in the Austro-Hungarian empire, as part of the struggle over language control between German-speakers, Czech-speakers, Polish-speakers, Magyar-speakers, and others. If Germany expands eastward and Jews bring honor upon themselves by serving German nationalist interests in the struggle, they might be given an annexed area of Czechoslovakia, Poland, Hungary, Ukraine, or the Balkans to call their own, nominally as part of the German empire but with a decent amount of autonomy.
Maybe a conflict in the Balkans expands and Germany intervenes, or Germany takes over a collapsing Austria-Hungary during WWI and redraws the borders to be more friendly to Sudaten-Germans. Or, a German nationalist government without the antisemitic tendencies (much more plausible than one might think, nationalism often had to do with language and culture rather than race) tries to annex the Sudaten territories, gets into a limited war, and redraws the map in favor of German speakers, with a Jewish homeland somewhere. The conflict never expands so the changes are not wiped out when Germany is defeated.