While being a bit harsh, this is indeed overall one of the biggest issues foreigners actually have: if you accept language and culture and adapt yourself into it, you love it. If you reject it Europe/that country is not your place. You will never feel home then or create a social web outside of the expat community.
I have seen so many cases of both cases here in Europe.
For the record - the point you appear to be making is that language and culture are the only two components of societal acceptance.
I am arguing that in a society based around ethnicity, ethnicity is another important part of societal acceptance.
This is not harsh, this is reality. Do you remember the reaction from French media and even the French ambassador to the US when a comedian pointed out that Africans won the 2018 football world cup? The defining characteristic of all their reactions was an attempt to erase or deny the African origins of footballers like Pogba, Kante, Kounde, Ben Yedder etc.
I have seen so many cases of both cases here in Europe.