changed the localisation but excel wants furthermore the European separator ";"

Hi, I have changed Office 365 from German to English, respectively installed (not only the language settings). I have uninstalled the German version.
Nevertheless, Excel still wants the European argument Separater ";" instead of the English ",".

What do I have to do so that Excel works with "," in the future?

I must admit that I did not completely uninstall Office 365 first.