Yes, very clear. I think you are missing something. Christ did institute in the Church, "a living, authoritative and permanent magisterium," don't forget that it's immune from error.
When he says "it's teachings" should be received as His own, that's exactly what he means, "it's teachings." He does not say their teachings, he says "it's teachings."
Satis Cognitum #8"It was consequently provided by God that the Magisterium instituted by Jesus Christ should not end with the life of the Apostles, but that it should be perpetuated.
We see it in truth propagated, and, ‘as it were, delivered from hand to hand. For the Apostles consecrated bishops, and each one appointed those who were to succeed them immediately “in the ministry of the word.”
Nay more: they likewise required their successors to choose fitting men, to endow them with like authority, and to confide to them the office and mission of teaching."
This particular passage clearly shows that the Magisterium is most definitely a living, teaching episcopal body. The authority to TEACH is perpetuated in the successors of the Apostles. The deposit of faith is physically delivered, by the teaching authority of the Church, the Magisterium, by ordinary and extraordinary means, "from hand to hand."
He continues:
Satis Cognitum #9"The practice of the Church has always been the same, as is shown by the unanimous teaching of the Fathers, who were wont to hold as outside Catholic communion, and alien to the Church, whoever would recede in the least degree from any point of doctrine
proposed by her authoritative Magisterium."
Proposed
verb
past tense: proposed; past participle: proposed
1. put forward (an idea or plan) for consideration or discussion by others.
A simple web definition shows that the Magisterium ACTS by PROPOSING doctrine.
The Magisterium is literally the teaching authority commissioned by Christ Himself to go forth and teach all nations.
Satis Cognitum #10"But as this heavenly doctrine was never left to the arbitrary judgment of private individuals, but, in the beginning delivered by Jesus Christ, was afterwards committed by Him exclusively to the Magisterium already named,
so the power of performing and administering the divine mysteries, together with the authority of ruling and governing, was not bestowed by God on all Christians indiscriminately, but on certain chosen persons.
For to the Apostles and their legitimate successors alone these words have reference: “Going into the whole world preach the Gospel.” “Baptizing them.” “Do this in commemoration of Me.” “Whose sins you shall forgive they are forgiven them.” And in like manner He ordered the Apostles only and those who should lawfully succeed them to feed – that is to govern with authority – alll Christian souls."
Again, given the context of the term Magisterium, used by Pope Leo XIII, I believe it clearly shows a physical office commissioned by Christ. The Magisterium was established by Christ to guard and protect the whole of Catholic Doctrine - which is immune from all error.
Pope Leo XIII is indeed teaching the truth, but he does not say anything like your CE quote. The CE quote, like LG, makes their teachings infallible so long as they're all teaching the same thing at basically the same time - this is NO teaching.
That's not necessarily how I read it, as the CE goes on to explain that the bishops must remain in communion with the pope to retain their teaching authority. There was more context, but you're right, Pope Leo XIII's explanation is much better, and more precise.