Now, what is the church's understanding of the dogma in question? Surely the first place to go would be the Catechism of the Council of Trent, no? Or perhaps those approved church men who published commentaries on the Council in the centuries following it?
Most definitely the dogma's meaning which has once been declared by the church cannot first appear almost 500 years later by someone who was not tasked by the church with interpreting the council.

Yeah, that's the issue I'm seeing here. If it were really such an egregious error, then how does it go uncorrected for 500 years and how is it that the official organs of the Church so severely misinterpret it?
Surely theologians alive during the period of Trent are far more knowledgeable than lay-theologians, a couple of self-taught monks and a single parish priest? People who have no authority (outside of Fr. Feeney) to teach anyone?

It again comes back to the realm of BoD being just a theological opinion, not an error, that we are not required to hold de Fide. If you don't believe in BoD or BoB, then you are not a heretic for rejecting it because Trent clearly defined the necessity of water baptism. Yet since it also did not define or condemn BoD and BoB, saying that those who hold such a theological position are heretics is ridiculous as well. Which, it is clear, even the Dimonds just say they are in error, not heretics (otherwise they would have to condemn these Saints who clearly taught it as heretics too).

The analysis of the controversial definition from Trent by the Dimonds themselves, who seek out a Latin expert, leave the interpretation of "or the desire of it" open to mean either an exclusive or inclusive sense of "or", "aut". https://schismatic-home-aloner.com/council-of-trent-did-not-teach-baptism-of-desire/

Therefore, holding to BoD as Tridentine theologians and Scholastics taught it is not heretical.

Now, it's clear by both reading the Dimonds and Feeney that there is a distinction to be made between what the Catechism taught as BoD/BoB versus what is going around today under the same name with the added modifier of "invincible ignorance." The thing I would like to know is just where the "invincible ignorance" BoD theory came from. As I suspect it developed out of an erroneous understanding of St. Thomas' and St. Alphonsus' teaching of the theory during the neo-Scholastic period in the 19th century. Yet I don't have much proof of that outside of Garrigou-Lagrange.