In German there is a rule on how to sort Umlauts (ÄÖÜß) in names:these are treated as if they qould be replaces by:
ä = aeö = oeü = ueÄ = AeÖ = OeÜ = Ueß = ss
and then sorted alphabetically.
Elvanto currently sorts people with Umlauts first, like:
Dörr, KatharinaDammer, RobinDeser, SigridDust, Karin
But it should sort
Dammer, RobinDeser, SigridDörr, KatharinaDust, Karin