if I were to become a citizen of the UK, or Germany, or France, I would not feel comfortable using the term British, German, or French to describe myself. Because those words are not just nationalities, but also ethnicities.

From a french perspective, What you said about French being a naitonality and a ethnicity sounds pretty racist, like the kind of things that Le Pen thinks but doesn’t dare to say too loud. France bragg a lot about every french citizen is equal and fully french (well we do have racist cunt so it’s not fully true, but it’s not the thing people would claim in public)