We must however have in mind that there is a great difference in the role of the laity, in many respects.
For example, Ecumenical Councils need the affirmation of the faithful in order to received in the Church.
By way of contrast, teachings promulgated by the Pope and the Magisterium and Catholic General Councils are sufficient unto themselves. The faithful are obliged to give assent of the mind and will.
I am afraid that you've not spent enough...non-selective...time in the documents of the Catholic Church. There is not quite the "contrast" that you present here.
There is simply nobody in our Church to whose teaching the faithful are required to give submission of the mind and will.
But let's look at what is taught by Vatican II and the Pope in Lumen Gentium....
Whether they qualify as technically de fide or not by reason of the "we believe, state, proclaim and define... to the whole Church", papal statements still cannot be denied by Catholics.
There is a requirement to give assent to the teachings of the Pope, even when he is not speaking ex cathedra. I find that quite interesting. "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.”~Dogmatic Constitution on the Church
Now Lumen Gentium, the Dogmatic Constitution on the Church
, is one of the principal documents of the Second Vatican Council. The Constitution was promulgated by Pope Paul VI on November 21, 1964, following approval by the assembled bishops by a vote of 2,151 to 5.
Whether one posits infallibility in Ecumenical Councils or Popes or both, this document is ungainsayable on all counts, and the Pope was most certainly exercising his magisterial authority. In other words, Catholics must give assent of mind and will to all papal teachings.