Pope Francis is wrong here. Co-Redemptrix is irreformable Church teaching already taught by a long line of Popes. See the below article:
"In his Apostolic Letter, Ineffabilis Deus, which defined the Immaculate Conception (1854), Blessed Pius IX makes reference to the Mother’s Coredemption by recalling the early medieval declaration of her as the “Reparatrix of her first parents” and its scriptural origins in the Genesis 3:15 prophecy of her coredemptive battle with the Serpent: “Also did they declare that the most glorious Virgin was the Reparatrix of her first parents, the giver of life to posterity, that she was chosen before the ages, prepared for Himself by the Most High, foretold by God when he said to the Serpent, ‘I will put enmities between you and the woman’—an unmistakable evidence that she has crushed the poisonous head of the Serpent” (Bl. Pius IX, Ineffabilis Deus,Dec. 8, 1854).
In his encyclical, Jucunda Semper, Pope Leo XIII (1878-1903) teaches that Mary shared with Jesus the painful atonement on behalf of the human race in the depths of her soul: “When Mary offered herself completely to God together with her Son in the temple, she was already sharing with Him the painful atonement on behalf of the human race… (at the foot of the cross) she willingly offered Him up to divine justice, dying with Him in her heart, pierced by the sword of sorrow.” (6)
The “Rosary Pope” of the nineteenth century also began a series of successive papal teachings which identify the Mother of the Lord as a “cooperatrix” (“co-operare,” to work with) in the distribution of the graces of Redemption as a direct result of her cooperation in the obtaining of the graces of Redemption: “She who had been the cooperatrix in the sacrament of man’s Redemption, would be likewise the cooperatrix in the dispensation of graces deriving from it.” (7) Again, Our Lady is Mediatrix of all graces because she is first the Co-redemptrix; there is acquisition of grace before its distribution. The “Mother suffering” becomes the “Mother nourishing.”
St. Pius X (1903-1914) carries on the papal tribute to Marian Coredemption in his first Marian encyclical, Ad Diem Illum (1904). In this famous text, the Pope of the Eucharist gives papal authority to the many previous theological testimonies to Mary’s share in the merits of Redemption in light of her joint suffering with the Redeemer:
Owing to the union of suffering and purpose existing between Christ and Mary, she merited to become most worthily the reparatrix of the lost world, and for this reason, the dispenser of all the favors which Jesus acquired for us by His death and His blood…. Nevertheless, because she surpasses all in holiness and in union with Christ, and because she was chosen by Christ to be His partner in the work of human salvation, she merits for us de congruo, as they say, that which Christ merited for us de condigno, and she is the principal dispenser of the graces to be distributed. (

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The Magisterium’s Use of the Co-redemptrix Title
The first usages of the Co-redemptrix title in the official pronouncements of the Roman Congregations also take place under the Magisterium of St. Pius X. Co-redemptrix is used three times by the Holy See in the initiatives of three Congregations of the Curia, and is thus contained in the publication of their official acts, Acta Sanctae Sedis (later to become Acta Apostolicae Sedis).
From:
https://www.motherofallpeoples.com/post/popes-of-the-marian-age-and-mary-co-redemptrix