And finding evidence of Mary’s burial would tatlly wreck the whole assumption of mary thing.
I could see why the church would not want the evidence to be found.
Or covered up if it were.
Absence of evidence does not support your position, no matter how it’s rationalized.
Those Constantine and Helena-era church people who transmitted to us the testimony that "There's nothing to see here, no bones and teeth of Mary, sorry folks" are the same ones who transmitted to us the written Scriptures. It was Constantine himself who ordered the production of 50 copies of the Bible for the churches in Constantinople, and Jerome says that the Council of Nicaea "counted the number of the Sacred Scriptures," which assumes the deterimination of a canon.
If they were such despicable liars that they would lie about Mary, why would you trust them for your canon of Scripture?
Moreover, there was no "doctrine" of the Assumption at that time, in the sense of something which had been proclaimed from the pulpits or defined in a Council. There was only an incipient doctrine in the form of the "sensus fidelium," the sense of the faithful, something they held as true, those of the flock of Bishop Macarius of Jerusalem, who would have had a very lively religious as well as financial interest in the relics, if they were to be had at all.
The Empress Helena almost certainly heard of a "doctrine" called the Assumption of Mary. Can you imagine the sensation it would have made, if she had found relics of Mary? Can you imagine the prestige that would accrue to her, and the immense "propaganda" triumph of having physical remains of Mary to display and venerate?
The "advantage: Church" from a human point of view would have been overwhelmingly in favor of finding relics.
Believe me, they would have, if they could have.
But they couldn't --- couldn't even claim it, couldn't even fake it.