It looks like this is a translation error. This objective is internally called "biggodlikeset", and "biggodlike" is the internal name for archeotech items. In the English version, the objective is "Gear up with "Archeotech Relic" Items of any Level (Minimum "5" pieces)", whereas in the German version, it's as you say: "Rüste dich mit Uralte-Reliquien-Gegenständen beliebiger Stufe aus (mindestens 5 Stück)." It should be "Archeotech-Reliquien-Gegenständen".
Okay werde es mal ausprobieren