Save the Orthodox and Coptic churches, I don’t believe there are any Post-Vatican II documents that refer to any other Christian community as a “church” because they don’t have valid Holy Orders. I believe they are called “Christian communities” or “ecclesiastical communities” in every official Church document since Vatican II. I could be wrong of course.
In other words, the Orthodox have valid Orders and thus are appropriately called a “church”. Other Protestants do not have valid Orders so they are not churches. By the Church’s definition at least.
It follows that the separated Churches and Communities as such, though we believe them to be deficient in some respects, have been by no means deprived of significance and importance in the mystery of salvation. For the Spirit of Christ has not refrained from using them as means of salvation which derive their efficacy from the very fullness of grace and truth entrusted to the Church.
Prior to Vatican II, the Catholic Church never taught that these other churches, communities, religions were "means of salvation".