Take your Bible and go through every verse in the NT and you will not find any verse that supports the idea that Mary was assumed. This was never taught by the apostles.
Do these count?:
2 Cor. 12:2 - Paul speaks of a man in Christ who was caught up to the third heaven. Mary was also brought up into heaven by God.
Matt. 27:52-53 - when Jesus died and rose, the bodies of the saints were raised. Nothing in Scripture precludes Mary’s assumption into heaven.
1 Thess. 4:17 - we shall be caught up in the clouds to meet the Lord in the air and so we shall always be with the Lord.
Rev. 12:1 - we see Mary, the “woman,” clothed with the sun. While in Rev. 6:9 we only see the souls of the martyrs in heaven, in Rev. 12:1 we see Mary, both body and soul.
2 Thess. 2:15 - Paul instructs us to hold fast to oral (not just written) tradition. Apostolic tradition says Mary was assumed into heaven. While claiming the bones of the saints was a common practice during these times (and would have been especially important to obtain Mary’s bones as she was the Mother of God), Mary’s bones were never claimed. This is because they were not available. Mary was taken up body and soul into heaven.
And since the ECF were taught by the Apostles, I’d say your last assertion is false too!:
“If the Holy Virgin had died and was buried, her falling asleep would have been surrounded with honour, death would have found her pure, and her crown would have been a virginal one…Had she been martyred according to what is written: ‘Thine own soul a sword shall pierce’, then she would shine gloriously among the martyrs, and her holy body would have been declared blessed; for by her, did light come to the world."
Epiphanius, Panarion, 78:23 (A.D. 377).
“[T]he Apostles took up her body on a bier and placed it in a tomb; and they guarded it, expecting the Lord to come. And behold, again the Lord stood by them; and the holy body having been received, He commanded that it be taken in a cloud into paradise: where now, rejoined to the soul, [Mary] rejoices with the Lord’s chosen ones…” Gregory of Tours, Eight Books of Miracles, 1:4 (inter A.D. 575-593).
“As the most glorious Mother of Christ, our Savior and God and the giver of life and immortality, has been endowed with life by him, she has received an eternal incorruptibility of the body together with him who has raised her up from the tomb and has taken her up to himself in a way known only to him.” Modestus of Jerusalem, Encomium in dormitionnem Sanctissimae Dominae nostrae Deiparae semperque Virginis Mariae (PG 86-II,3306),(ante A.D. 634).