Here is another pre-Vatican II source on non-infallible matters, and how assent can sometimes be suspended. It is cited by Xavier Da Silveira in his study "Can the Pope go bad"? Note again that conditional and prudential religious submission we give to non-infallible documents, even documents of mere Bishops other than the Pope, because of a presumption in favor of their episcopal authority, is substantially different from the absolute and unconditional assent we give to infallible documents, because of the impossibility of error.
"“ (. . .) one must assent to the decrees of the Roman Congregations, as long as it does not become positively sure that they have erred. Since the Congregations, ‘per se”, do no furnish an absolutely certain argument in favor of a given doctrine,
one may or even must investigate the reasons for that doctrine. And thus, either it will come to pas that such a doctrine will be gradually accepted in the whole Church, attaining in this way the condition of infallibility, or it will happen that the error is little by little detected.
For, since the religious assent referred to is not based on metaphysical certainty, but only on a moral and general one, it does not exclude all suspicion of error.
For this reason, as soon as there arise sufficient motives for doubt, the assent will be prudently suspended; nevertheless, as long as much motives for doubt do not arise, the authority of the Congregations is sufficient to oblige one to assent.
The same principles apply without difficulty to the declarations which the Supreme Pontiff omits without involving his supreme authority, as well as the decisions of the other ecclesiastical superiors who are not infallible”
Wiki on the
Obsequium Religiosum again:
https://en.wikipedia.org/wiki/Obsequium_religiosum
"The phrase appears in Lumen gentium 25a in the following context, here translated as both "religious assent" and "religious submission":
Bishops, teaching in communion with the Roman Pontiff, are to be respected by all as witnesses to divine and Catholic truth. In matters of faith and morals, the bishops speak in the name of Christ and the faithful are to accept their teaching and adhere to it with a religious assent. This religious submission of mind and will must be shown in a special way to the authentic magisterium of the Roman Pontiff, even when he is not speaking ex cathedra; that is, it must be shown in such a way that his supreme magisterium is acknowledged with reverence, the judgments made by him are sincerely adhered to, according to his manifest mind and will. His mind and will in the matter may be known either from the character of the documents, from his frequent repetition of the same doctrine, or from his manner of speaking."
Withholding assent
Donum Veritatis also allows that even if, "not habitually mistaken in its prudential judgments...some Magisterial documents might not be free from all deficiencies," and withholding assent is allowed for a theologian, "who might have serious difficulties, for reasons which appear to him wellfounded, in accepting a non-irreformable magisterial teaching." In such "even if the doctrine of the faith is not in question, the theologian will not present his own opinions or divergent hypotheses as though they were non-arguable conclusions," and is to "refrain from giving untimely public expression to them," and "avoid turning to the mass media," but with a humble and teachable spirit it is his duty "to make known to the Magisterial authorities the problems raised by the teaching in itself, in the arguments proposed to justify it, or even in the manner in which it is presented," with "an intense and patient reflection on his part and a readiness, if need be, to revise his own opinions and examine the objections which his colleagues might offer him", prayerfully trusting "that if the truth really is at stake, it will ultimately prevail."
Finally, here is Dietrich Von Hildebrand, whom 20th century Popes have called "20th century Doctor of the Church", "one of the greatest intellectual influences of our time" etc etc which arguably constitutes a Papal endorsement of his approach toward Vatican II.
""The Second Vatican Council solemnly declared in its Constitution on the Church that all the teachings of the Council are in full continuity with the teachings of former councils. Moreover, let us not forget that the canons of the Council of Trent and of Vatican I are de fide, whereas none of the decrees of Vatican II are de fide;The Second Vatican Council was pastoral in nature. Cardinal Felici rightly stated that the Credo solemnly proclaimed by Pope Paul VI at the end of the Year of Faith is from a dogmatic point of view much more important than the entire Second Vatican Council.
Thus, those who want to interpret certain passages in the documents of Vatican II as if they implicitly contradicted definitions of Vatican I or the Council of Trent should realize that even if their interpretation were right, the canons of the former councils would overrule these allegedly contradictory passages of Vatican II, because the former are de fide, the latter not." -Dietrich Von Hildebrand
"Dietrich von Hildebrand is the 20th century Doctor of the Church." -Venerable Pope Pius XII
“When the intellectual history of the Catholic Church in the twentieth century is written the name of Dietrich Von Hildebrand will be most prominent among the figures of our time.” –Pope Benedict XVI"
From:
https://catholicismhastheanswer.com/vati...clarified/