(Credit: Ken Howard) The Metropolitan Opera has unveiled week 6 of its streaming service which features an all-star gala and six operas with such stars as Sonya Yoncheva, Anna Netrebko, Nina Stemme, Renée Fleming, Natalie Dessay, Joyce DiDonato, and Juan Diego Flórez, among others. Here is a breakdown. Monday, April 20 – Strauss’s Elektra Starring Nina Stemme, Adrianne Pieczonka, Waltraud Meier, {…}