Not the OP, but Europeans are fairly tribal and "becoming" an Austrian or Czech isn't the same as becoming an American. An expat who speaks the language and gained citizenship will be known as "someone who has the Austrian/Czech/German" passport. Only the kids who speak without accent will probably be fully embraced as natives.
In my case, I am a native Czech who speaks flawless Czech, but some people actually refuse to acknowledge me as a Czech on account of my Bulgarian surname. (Funnily some of them cannot even write properly, but hey, they are Nováks or Kučeras and I am not.) Not a majority, but this kind of tribalism is more widespread here than in countries that were founded on mass immigration.
It depends from country to country; in Romania, for example, where we used to have many communities of Hungarian, Bulgarians, Czech, Polish, Turks and Tatars, if you are reasonably white (or Mongolian looking) and speak a decent Romanian you are considered to be integrated. If you look very different (Black or Chinese) you are accepted, but not considered a local even if you were born and raised in Romania and speak the language natively - this is because non-White people are a tiny, tiny minority (a few in a million).
In my case, I am a native Czech who speaks flawless Czech, but some people actually refuse to acknowledge me as a Czech on account of my Bulgarian surname. (Funnily some of them cannot even write properly, but hey, they are Nováks or Kučeras and I am not.) Not a majority, but this kind of tribalism is more widespread here than in countries that were founded on mass immigration.