the idea of a 2nd libero being a "false OH" (i.e. coming for a player in the back row without being an official libero) is done well by kwiek and the DOM team. when binet comes in to serve for the MB, then that allows castillo to sub in for de la cruz or another OH in the back row, so they have both castillo and binet in the backcourt. the disadvantage is having one less back row hitter (which de la cruz excels at), but that allows her to take a break if needed. also, kwiek will sometimes put martinez in front row for marte, so she can block/hit upfront, with castillo setting for that one rotation.
Two liberos, it was the usual strategy of Yan Fang in RC Cannes : Cardullo + Péron ; Arcangeli + Ortschitt, last year, and so on.
But next year it seems Ortschitt will be alone as libero. Difficult to believe