This sounds very post-modern even as I write it, but I I don’t think the GIRM’s statements on music are really meant to be taken in a literally, legal sense. The statements on music are very slightly vague and very liberal. The history of their practical interpretation has also been very liberal. I think it is within the spirit of the document to assume that vernacular graduals are ok. Like most of the NO, it’s just not built to stand up to the sort of legal scrutiny that is being inflicted upon it in this thread. The writers did not think through the possible implications as far as have writers of this thread.
So if the pastoral situation benefits from a vernacular gradual - like at St John’s seminary during the pandemic - then bring forth the treasures from the church’s storehouse.
The same situation with a sequence, say the one for St Anne’s day from the Summit Choirbook: how is the Church harmed by the inclusion of this beautiful treasure from the church’s past?

It’s a dangerous game, yes, but the interpretative weight should be on the side of tradition, not against it.

Sigh, the question asked isn’t the question that actually gives that answer! That was Andrew’s entire point. (And with Jeff, this is a recurring theme; he has, or doesn’t have, I suppose, his reasons, plus the bishops’ conference is not competent in the matter.)