Pope Pius IV received, and confirmed, ex cathedra, all the decrees. Which is the norm of what happens with an Ecumenical Council.
And furthermore, ex cathedra does not require a Pope. It’s a term that can be used generally for authoritative teaching. It is Latin for ‘from the chair’.
I do not know what else to say as I do not know where you are on this? Have you read much of the other thread? It really delves into the issue well with the pros and cons.
"And whereas the said holy Synod, in its reverence towards the Apostolic See, and following also in the traces of the ancient Councils, has, in a decree made thereon in public Session, requested of us the confirmation of all Its decrees, passed in our time and that of our predecessors; We, being made acquainted with the request of the said Synod, first by the letters of our Legates, then, upon their return, by what they diligently reported in the name of the Synod; after mature deliberation had thereon with our venerable brethren the cardinals of the holy Roman Church, and, above all, having invoked the assistance of the Holy Spirit; after that we had ascertained that all those decrees were Catholic, and useful and salutary to the Christian people, We, to the praise of Almighty God, with the advice and assent of our brethren aforesaid, have this day, in our secret consistory, confirmed by Apostolic authority all and singular those decrees, and have ordained that the same be received and observed by all the faithful of Christ; as also, for the clearer information of all men, We do, by the tenour of this letter, confirm them, and ordain that they be received and observed.
And, in virtue of holy obedience, and under the penalties by the sacred canons appointed, and others more grievous, even those of deprivaiton, to be inflicted at our discretion, We do also command all and each of our venerable brethren, the patriarchs, archbishops, bishops, and all other prelates whatsoever of the churches, of what estate, grade, order and dignity soever, they may be, even though distinguished with the honour of the cardinalate, diligently to observe the said decrees and statutes in their own churches, cities, and dioceses, both in their courts of justice and elsewhere, and to cause the same to be inviolably observed, each by his own subjects, in so far as they are in any way concerned therein; silencing gainsayers, and the refractory, by means of judicial sentences, and by the censures also and ecclesiastical penalties contained in the said decrees; calling in also, if need be, the help of the secular arm. And, by the bowels of the mercy of our Lord Jesus Christ, We admonish and conjure our said most beloved son the emperor elect, and the Christian kings, republics, and princes, with that piety with which they assisted, by their ambassadors, at the Council, with the same piety and equal zeal, for the sake of God’s honour, and the salvation of their people, in reverence also towards the Apostolic See, and the sacred Synod, to support, when needful, with their assistance and countenance, the prelates in executing and observing the decrees of the said Council ; and not to permit opinions adverse to the sound and salutary doctrine of the Council to be received by the people who are under their sway, but utterly to interdict such."
Pope Pius IV