Above, I quoted the relevant parts of Mystici corporis contradicting what you say.
You would have to, to convince me.
I must mention that I'm a bit puzzles that this doctrine apparently is something unknown or new to some, but PPXII explains it very well imo. The doctrine stated very simply is this: Christ and the Church are one.
There are more references out there I'm sure, but these were the most easily found, I bolded the points we're discussing......
Pope Pius XII53. As Bellarmine notes with acuмen and accuracy, this appellation of the Body of Christ is not to be explained solely by the
fact that Christ must be called the Head of His Mystical Body, but also by the fact that He so sustains the Church, and so in a certain sense lives in the Church, that she is, as it were, another Christ. The Doctor of the Gentiles,
in his letter to the Corinthians, affirms this when, without further qualification, he calls the Church "Christ,"
following no doubt the example of his Master who called out to him from on high when he was attacking the Church:
"Saul, Saul, why persecutest thou me?" Indeed, if we are to believe
Gregory of Nyssa, the Church is often called simply "Christ" by the Apostle; and you are familiar Venerable Brethren, with
that phrase of Augustine: "Christ preaches Christ." 60. And now, Venerable Brethren, We come to that part of Our explanation in which We desire to make clear why
the Body of Christ, which is the Church, should be called mystical.
This name, which is used by many early writers, has the sanction of numerous Pontifical docuмents. There are several reasons why it should be used; for by it we may distinguish the Body of the Church, which is a Society
whose Head and Ruler is Christ, from His physical Body, which, born of the Virgin Mother of God, now sits at the right hand of the Father and is hidden under the Eucharistic veils; and, that which is of greater importance in view of modern errors, this name enables us to distinguish it from any other body, whether in the physical or the moral order.
67. Here, Venerable Brethren, We wish to speak in a very special way of our union with Christ in the Body of the Church, a thing which is, as Augustine justly remarks, sublime, mysterious and divine; but for that very reason it often happens that many misunderstand it and explain it incorrectly. It is at once evident that this union is very close. In the Sacred Scriptures it is compared to the chaste union of man and wife, to the vital union of branch and vine, and to the cohesion found in our body. Even more, it is represented as being so close that
the Apostle says: "He (Christ) is the Head of the Body of the Church," and the
unbroken tradition of the Fathers from the earliest times teaches that the Divine Redeemer and the Society which is His Body form but one mystical person, that is to say
to quote Augustine, the whole Christ. Our Savior Himself in His sacerdotal prayer did not hesitate to liken this union to that wonderful unity by which the Son is in the Father, and the Father in the Son.
77. This communication of the Spirit of Christ is the channel through which all the gifts, powers, and extra-ordinary graces found superabundantly in the Head as in their source flow into all the members of the Church, and are perfected daily in them according to the place they hold in the Mystical Body of Jesus Christ. Thus the Church becomes, as it were, the filling out and the complement of the Redeemer, while Christ in a sense attains through the Church a fullness in all things.
Herein we find the reason why, according to the opinion of Augustine already referred to, the mystical Head, which is Christ, and the Church, which here below as another Christ shows forth His person, constitute one new man, in whom heaven and earth are joined together in perpetuating the saving work of the Cross: Christ We mean, the Head and the Body, the whole Christ.Eph 5:23
Because the husband is the head of the wife,
as Christ is the head of the church. He is the saviour of his body.
Col 1:18
And he is the head of the body, the church, who is the beginning, the firstborn from the dead;
that in all things he may hold the primacy