It's a fascinating topic. Do you have any papers or books I could read on the matter? As a student of language, I can't take anecdotal evidence on such a topic into consideration if it isn't backed up by proper research.

Meanwhile, a foreign vocab word is much less likely to be adapted because it doesn't fit into the structure

I get the feeling it's not about the structure. German has easily adapted die Dacha into common vocab - even keeping the original word's gender, when the tendency is to make it neuter, like das Handy. Why would they do it so comparatively intimately? Because there were, at a certain point, who worked and lived in Germany and had to bring the reality of their lives into the language. It's not that it was difficult for the structure to adopt the word: it's just some words aren't nearly intimate for the speakers to care enough about the original. Which is how you get der Fernseher when the word "television" was in use quite about the thing's invention already.

And English is damn international at this point. People use it all over the world and bring bits and pieces around all the time. emoji is fairly new, but pierogi dates back to at least 1930's, what with the mass fleeing of the population of Poland and the Soviet Union due to prosecution and the German threat. And what the hell else d'you gonna call it? "Pocket pie"? "Stuffed bread"?