It's not fucking heresy ffs this guy has less theological knowledge than a 13th century peseant.
It may very well be Warhammer 40k brain, the kind that cryptofascist dipshits get when they get excited about Exterminatus and want to say "heresy/xeno/witch" a lot to justify their genocide fantasies.
Which has in turn been embraced by this kind of guy (especially as the series went on to be less satire and portray the space fascists as heroes more frequently)
Honestly when you look at the medieval peasant religious movements in the 13th and 14th centuries the presence of visionary women is really striking, of which Joan of Arc is only the most obvious. Many of the most important mystic writers were women. Probably were also the best. So I expect many of them would have known far more about Christianity that this fuckhead.
Don't forget that the catholic propaganda back then worked exactly like the current imperialist one does. Most of the people killed for heresy were not for speaking nonorthodox but for the political and economical resistance to the church.
Most succint take on this had XVI century polish bishop of Kraków, Andrzej Zebrzydowski, while commenting mass conversions of polish nobility to calvinism: "Let them believe even in the goat, provided they pay tithes". And indeed they only rebelled over century later after decades of counterreformation.
It didn't even have to be to the Church, as Joan of Arc illustrates. And of course what happened to Jan Hus was fucked, he had some odd ideas but none were actively heretical, and betraying a guest is the ur-example of how you get cursed by the gods (admittedly the Reformation and Wars of Religion was one hell of a curse)
Broadly, the sacraments are "required" for salvation but in the sense that a) engaging in them sincerely is a pretty good way to ensure salvation and b) Catholicism insists both faith and works are needed for salvation and confession etc are required for that.
You can be saved via private prayer or divine intervention, because stop telling god what to do.
Tradcaths disagree with this because of the doctrine of "no salvation outside the church". This is due to a very limiting view of what the church is (and of what Jesus is, but that's another post).
Firstly the above sentence is a tautology, since the church is by definition the community of saints on earth. Secondly it's the universal church, and calls to all peoples through god's grace regardless of how much water was sprinkled on their head.
Finally a person who honestly seeks gods truth and salvation and fails to find it has what is called invincible ignorance (a much broader concept than "never saw a bible" and in fact a state some tradcaths are probably in.) and will be saved regardless. And there is always direct personal revelation right up to death, of course.
This is not apologetics and I am not a theologian, just an attempt to explain church doctrine as actually given to people who don't think the only valid council was Vatican I
There are good reasons they don't teach it, since it generally quickly leads to universalism without some other theology backing it up, and certain (rather than hopeful) universalism is a heresy.
But most of the time they're just trying to instill the sad grimdark Irish Catholic thing where you must be sad and guilty all the time because the British spent 200 years preventing you from going to mass.
I also want to add that I have any number of issues with "normal" catholic doctrine. Church is fucked and needs a full clean out and reset. I'm just trying to give the centrist doctrine a fair shake.