Preumably because the site is in German -- https://www.sc-salzstiegl.at/

If my country is set to Germany it's the first result in DDG

If my country is set to the UK I get lots of pages in English about it which are probably more likely to be what I would want

If I search for "Skiclub Salzstiegl" though, it is the first result

I disagree. I specifically searched for Salzstiegl ski club, I don’t really care about the language, just return the website I am looking for. Why does Google return the correct result first, regardless of language?

I also tried setting DDG to “All Regions” and the results were not better.

By phrasing it that way you're searching in English, it seems a reasonable choice to return sites that are in English.

If I search DDG for "US President", the first results are the English Wikipedia page for "President of the United States" and "List of presidents of the united states"

If I search for "US-Präsident", I get "Liste der Präsidenten der Vereinigten Staaten" and "Präsident der Vereinigten Staaten - Wikipedia" from Germany wikipedia, and fairly high up is a link to zeit [0]

That Zeit link doesn't appear if I search in English.

It seems that DDG puts the language used of the search fairly high in the weighting. That's reasonable to me. If I search "Nicolas Sarkozy im Gefängnis", I get German stories about the French President.

I can see both arguments, I don't think differing weights for language is an indictment of a search algorithm specifically though.

[0] https://www.zeit.de/politik/ausland/2022-02/joe-biden-us-pra...