Not really off topic but think of it this way.
The church doesn’t go around declaring this and that. The body of Christ has discussions and brings things to the church. So for example the divinity of Christ took centuries to Hammer out in church council until finally it was said “this is the faith handed to us and it should be described this way”
So with those Marian doctrines. There was really no dispute but there was murmurs and discussions about Mary being more than the church describes and so the pope declared those dogmas. Dogmas that were always held, but that point in history is the point at which a clarification needed to be made by the church.
You can look all the way back to the early fathers to see them talk about those dogmas.
The Marian dogmas are not all that clear in the early fathers.
So then, after the assent of the holy Virgin, the Holy Spirit descended on her, according to the word of the Lord which the angel spoke, purifying her, and granting her power to receive the divinity of the Word, and likewise power to bring forth.
John of Damascus (Exposition of the Faith, Book 3, Chapter 2)
newadvent.org/fathers/33043.htm
If she was without sin, why the need to purify her?
Similarly
This is the Holy Ghost, who came upon the Holy Virgin Mary; for since He who was conceived was Christ the Only begotten, the power of the Highest overshadowed her, and the Holy Ghost came upon her, and sanctified her, that she might be able to receive Him, by whom all things were made
Cyril of Jerusalem (Catechetical Lectures, Lecture 17, Paragraph 6)
newadvent.org/fathers/310117.htm
Even Thomas Aquinas and Bernard of Clairvaux denied the Immaculate Conception in the way that Pius IX defined it.
As for being sinless.
And this He said, not as being ashamed of His mother, nor denying her that bare Him; for if He had been ashamed of her, He would not have passed through that womb; but as declaring that she has no advantage from this, unless she do all that is required to be done. For in fact that which she had essayed to do, was of superfluous vanity; in that she wanted to show the people that she has power and authority over her Son, imagining not as yet anything great concerning Him; whence also her unseasonable approach. See at all events both her self confidence and theirs. Since when they ought to have gone in, and listened with the multitude; or if they were not so minded, to have waited for His bringing His discourse to an end, and then to have come near; they call Him out, and do this before all, evincing a superfluous vanity, and wishing to make it appear, that with much authority they enjoin Him.
John Chrysostom (Homilies on Matthew, Homily 44, 12:46-49)
newadvent.org/fathers/200144.htm
And on both being sinless and being Mother of God
But He rather admonishes us to understand that, in respect of His being God, there was no mother for Him, the part of whose personal majesty He was preparing to show forth in the turning of water into wine….Nor, again, should we be moved by the fact that, when the presence of His mother and His brethren was announced to Him, He replied, “Who is my mother, or who my brethren?” etc. But rather let it teach us, that when parents hinder our ministry wherein we minister the word of God to our brethren, they ought not to be recognized by us.
Augustine (A Treatise on Faith and the Creed, Chapter 4, Paragraph 9)
ccel.org/ccel/schaff/npnf103.iv.iv.v.html
He was in an extraordinary manner begotten of the Father without a mother, born of a mother without a father; without a mother He was God, without a father He was man; without a mother before all time, without a father in the end of times…9. Why, then, said the Son to the mother, “Woman, what have I to do with you? mine hour is not yet come?” Our Lord Jesus Christ was both God and man. According as He was God, He had not a mother; according as He was man, He had. She was the mother, then, of His flesh, of His humanity, of the weakness which for our sakes He took upon Him.
Augustine (Tractates on John, Number 8, Paragraphs 8-9)
newadvent.org/fathers/1701008.htm
He it is Who is without mother according to His Godhead, for He was begotten of God the Father, of one substance with the Father; without a father according to His Incarnation, for He was born of a Virgin; having neither beginning nor end, for He is the beginning and end of all things, the first and the last.
Ambrose (On The Mysteries, 8:46)
newadvent.org/fathers/3405.htm
These men all thought very highly of Mary, as do I, but necessarily in accordance with later defined dogma.
However there was virtual unanimity on Mary being ever virgin.