Helmut, thanks for spotting this.
Categories are in single language streams. The proper category name in the English language stream would be "Holy Roman Empire."
If there is a wish to create a separate Latin Language stream, ascending up to the Latin word for Categories (!) , then one could have a category using the Latin language version for Holy Roman Empire. Which apparently is not Imperium Romanum Sacrum! (But I claim no expertise in that!).
I believe the purpose of having separate language category streams, however, is to make categories accessible and useful to those whose primary language is a language other than English. I don't believe we have a constituency whose primary every day language is Latin!
We have a constituency on WikiTree who have found it useful to create category streams in Swedish, in French, in Indonesian, and some other languages as well. There might be an interest in creating a separate category stream in German for these categories. A German language category stream has already been started, but there isn't much in it:
https://www.wikitree.com/wiki/Category:Regionen
Obviously some work was done to create this category, so the project that is focused on this should take the lead in re-naming several categories in English, and moving the material from one category page to the other, if they are to appear in the English language category stream. Then Ales' instructions can be followed to have the affected profiles moved from the Latin language to English language versions.