I can't speak for Orthodoxy, but at least one devout Orthodox has repeatedly said on here that he doesn't stay up at night worrying about our salvation.
Oh, and you asked heresy in relation to what--in relation to the Catholic faith, as defined by the ancient creeds and the teaching of the Church down the centuries.
You seem to have entirely missed the point of that question.
If that question was returned to as you've re-stated/adjusted it above, it could be yet further asked -- WHICH Church "down through the centuries", being as the Orthodox do not subscribe to the things I did make mention of? In ending results arguably enough leaves either ekklesia carrying taint of "heresy".
The subject had been heresy, and how that could according to you...lead to.... not getting to heaven, as you had more or less said (and I had quoted):
Both the Orthodox, and the Latin Church cannot be right at the same time ---not when they disagree on those points of "teaching of the Church" that I had touched upon.
Or else, to deny that the Bishopric of Rome be sole (or only chief) "successor to Peter", and to deny there be such a thing as Purgatory not matter hardly at all---such disagreements not be heresy. So, what now? An attempt to put the best face on the Orthodox Church's view towards Romish claims for singular papacy?
If read closely enough, one fairly recent statement (signed off on by only a relative few Orthodox, and since then criticized by far more others) it's plain to me those who had agreed to a particular wording were endeavoring to be polite, and were also under great pressure to submit to the claims Rome makes for itself.
Here on this forum I've seen how that kind of high pressure tactic can play out. I've had that particular stunt pulled on me (the attempt to pull that stunt, anyway, and with less on the table being as I speak chiefly only of and FOR myself) hundreds of times over. I can say that without trace of exaggeration.
Is it any wonder so many have turned their backs on the whole mess altogether? I know for a certainty I would have, if God had not responded to my own prayer that it be Himself who proved to me -- well, Himself.