Hi! Feel free to ignore this if you want, but you know a lot about Siegfried and a lot about language, so I thought you would be a good person to ask.
Do you know why Siegfried's surname is sometimes listed online as Schützen instead of Schtauffen? From my cursory Google searching, it seems like "schützen" is a real word, while "schtauffen" just brings up Soulcalibur-related things, so is it a case of Schützen being a more accurate German name?
Short answer: I know enough German to guess why Schtauffen is spelled the way it is, but I don't know what whoever came up with Schützen was thinking.
Long answer: I'll get straight to the point, the only other places I've seen Siegfried's surname listed as "Schützen" seem to be repeating it from the Fandom Wiki. As far as I can find, it's not used any version of the games.
Now, "Schützen" is an actual German word but here's where this name choice starts to baffle me. If whoever added it to the Wiki was aiming for an actual surname, they missed "Schütze" by one letter; it originally meant "archer" but came to also mean "rifleman" (literally "shooter").
I'm splitting hairs on this, but "Schützen" as a noun (note the capitalization) can be:
The plural of "Schütze" (e.g. riflemen).
A shuttle (the kind used in weaving).
Not to be confused with the verb schützen, which means "to protect", "to defend", or "to guard".
This is not an exhaustive list, but I think I've made my point as to why it sounds a little off.
That all being said, "Schtauffen" isn't an accurate spelling because in German orthography, "St-" at the start of a word is pronounced "Sht-" (hence "SHTAU-fen"), which makes that "ch" superfluous. Here's how Siegfried's surname is written in katakana: シュタウフェン, Shutaufen. Of course, "sht" isn't a consonant cluster that exists in Japanese, so it starts with the syllable "shu" (シュ). At full risk of sounding pedantic, that first "u" sound is devoiced, so you'll barely hear it in the Japanese audio.
Case in point, here it is in the middle of the SC6 Hwang Soul Chronicle where Siegfried introduces himself. (I'm surprised I didn't hear it in the ending cutscene of Hilde's SC4 story; it's the first place I looked!)
Doesn't sound much like "Schützen" at all, does it?
I know I went on at length about this years ago, but I'm convinced that the name came from Staufen of the Faust legend, either the town Staufen im Breisgau or its lords in the 16th century. And yes, the katakana for Staufen matches. (Google assumed I meant the Hohenstaufen dynasty at first, which isn't related, but adding "AND ファウスト" worked for me.)