How literally should we take 'no salvation outside the Catholic Church' given the exceptions like invincible ignorance?

Take it as literally as the Church allows, and from the time of Boniface VIII and Eugene IV that was quite literal: heretics, Jews, and schismatics cannot be saved because they refuse to be members of the Catholic Church, and that still holds today for anyone who competes against the Church and says you need not join her to be saved. It is simply a matter of authority. There can only be one Church that Jesus built, one authority; if we are the only authority, then you cannot be your own, and to know the truth you must come under that one authority, one of whose provisions is salvation. So it follows logically that outside her there is no salvation. What makes it seem confusing is that there are exceptions to the rule, as there are to nearly every rule, even to 'thou shalt not kill.' Pius IX gave us the encyclical Quanto conficiamur moerore in 1864, teaching that a person who truly wants eternal life and follows God as best he can, while being invincibly ignorant of the Church or the gospel, can be saved, because God will not judge a man for what he genuinely could not know. That does not mean the category is crowded; we only know such a category exists, and God is its judge. Boniface and Eugene, by the way, spoke in the 1300s and 1400s when the Orthodox had split and groups like the Hussites and Wycliffe's followers were claiming they did not need the Church, so the popes drew the line firmly. So yes, no salvation outside the Church still holds and always will, alongside the exceptions God alone judges.