As for searching, searching with Nominatim for names given in `alt_name:de` works just as fine as for names given in `name:de`, so no need to be concerned with that.

Still, whatever name is deemed to be the most common contemporary variant (I hope you do realize that `name:xx` keys are for contemporary, and not "original" names?), changing only `name:de` and leaving `alt_name:de` intact, making them both hold the same value, is no matter what an error…