I have done the research.
That her tomb was empty was reported at the Council of Chalcedon by Juvenal, then bishop of Jerusalem. I am not certain that this fact was known to the church as a whole in the 2nd, 3rd or 4th centuries.
The feast of her assumption has been celebrated even further back than this in Jerusalem, and apparently, what Juvenal reported was well known there.
Any book that you have that says nothing about Juvenal is suspect on this topic, so whatever book you are using isn’t really helpful to this conversation.
Nevertheless, the earliest evidence of any such belief appears only in the ninth century, in a Syriac manuscript, copied in 874 which reports that Mary accompanied John to Ephesus, where she died and was buried. (Shoemaker S. The Ancient Traditions of the Virgin Mary’s Dormition and Assumption. Oxford University Press, 2006, p. 75)
There’s evidently a house outside of Ephesus that has a plaque proclaiming it to be the house of Mary.
Pope Pius XII declared it a Holy Place as did Pope John XXIII (it is an important religious site for Muslims too); Wikipedia reports “Pope Paul VI visited the shrine on July 26, 1967, and ‘unofficially’ confirmed its authenticity.”
But irrespective of what location may have been “Mary’s house”, the historical accuracy of the “assumption of Mary”, is at best an assumption that seems to contradict scripture.
John 3:13 And no man hath ascended up to heaven, but he that came down from heaven, even the Son of man which is in heaven.
I can find nothing prior to the 4th century of anything on the Assumption of Mary.