The qualifying win
Argentina's federation records a 3–0 home win over Venezuela at La Bombonera on March 25, 2022. By then Argentina had already secured its Qatar place. Winning a qualifier is not automatically the same event as mathematically clinching qualification; this particular victory came afterward.
Source [1]When the place was secured
FIFA's November 16, 2021 qualifying review identifies Argentina's 0–0 draw with Brazil, combined with Chile's home defeat, as the results that secured qualification. This corrects the implication in the inherited address that the Venezuela win itself clinched the berth. Qualification depends on accumulated points, remaining fixtures and rivals' possible totals, rather than simply the latest victory. Argentina's later opening defeat to Saudi Arabia and semifinal win over Croatia belong to the finals in Qatar, a separate competition stage from these qualifiers.
Source [2]