In the end everybody is different, but I think Americans are in general much warmer than Dutch/Germans or Scandinavians.

More open, more generous, more emotionally expressive, more warm, more traditional ( which I appreciate).

It is most probably prejudice. A lot of people don’t like dating foreigners either and cultural differences are a thing too. I am a Romanian woman living in the Nederlands and I had problems finding a partner as well. I had lots of Dutch men interested in me though, but while I find them physically attractive and most of them were good people, they don’t attract me at all personality wise due to cultural differences. I am now together with an American and it is a much better match, there is no comparison actually. My suggestion would be for you to try dating other nationalities.