German people outside of Germany were definitely a concern of the Nazis. There was even a word for them: Volksdeutsche. Long before the war, the Nazi regime made a point to reach out to them, with newsletters, clubs, and other ventures to build solidarity and general good sentiment. Often these came with some underlying hints of eugenics. Don't marry your "lesser" neighbors! Have healthy strong, German children! Send your sickly to us (to, uh, take care of)! Raise your children to be good Aryans!

The amount of effort put into grooming the Volksdeutsche largely seems to have depended on the area. In places like Poland, Czechoslovakia, Romania, and so forth where nationals were deemed "unfit" and slated for extermination, ethnic Germans were certainly given preference. The plan was to repopulate huge swathes of Eastern Europe with Germans, and here were Germans! Provided they cooperated, they were fairly handsomely rewarded. According to one paper on German-Russians working with anti-fascist groups, "Under the German occupation the German-Russians enjoyed special status and certain advantages. For instance, in similar situations they received higher pay and special rations of food and consumer goods". Or, as another article says, "They benefited materially from the plunder of their Jewish, Czech and Polish neighbors, and even if they sometimes resented their loss of autonomy (as when Germans from the Reich secured choice jobs and property during the Nazi occupation), they rarely protested. "

This even extended to non-German children who were deemed to "look" German, who were in some cases kidnapped and rehomed as part of the ambitious Lebensborn program.

In many cases eastern Germans may have embraced the take over because their former neighbors now greatly resented them and they were in danger from partisans who viewed them as collaborators. (In fairness, they may have collaborated a lot, some historians suggest they disproportionately participated in mob violence against Jews and resistance fighters and were more likely to report to the Gestapo). This idea was pushed even more after many German civilians were killed during fighting in a Polish city with a large German minority population (in the Bloody Sunday incident). Obviously this made for very good German propaganda and pushed Germans or German passing people even further into the arms of the Nazis.

Of course not all cooperated, as I said above, there were enough Germans fighting back in Russia to merit a whole paper on the subject! But ethnic Germans-Poles, or Czechs who resisted measures like conscription or racial categorization were sent to concentration camps like everyone else. So overall they went along with Germany, even celebrated her victories, and reaped the benefits of being German.

On the other hand in France, Belgium, and Austria, Germany largely seems to have considered everyone white enough to be human (In Norway SS officers were even encouraged to have children with local girls, because their genes were so good, so there's a lot to get into there), so there was a lot less preferential treatment. Germans-by-heritage were still special because of the shared language and culture, and maybe they got offered positions in occupation regimes or gentle hints to join the German army, but there wasn't the same pressure to be at the leading edge of the force that would resettle the east. There was, at least according to one paper, some efforts by the Deutsche Volksgemeinschaft in Lorraine to establish more of a racial hierarchy that placed ethnic Germans over the French. These motions don't seem to have gone as far as the extreme eugenics on the other side of Europe, however.

Ultimately, the German-InsertCountryHeres were just pawns in a greater game. When the Nazis won, most of them were left behind while the armies fled. Then they were murdered in huge numbers by armies looking for someone to blame for the brutality, or placed in internment camps. Many ended up fleeing their home countries. Both the Nazis and their later persecutors defined them by their heritage and nothing else. In the end, that's a terrible way to see a person.