"I was under the impression that the assumption doesn't deny the physical
death of Mary; just that she was assumed into heaven (body and soul) after
her demise."

Fr. Chad would have the final word on this, but I think the Roman thing is that she was assumed without death. The Orthodox hold to the Dormition of Mary - the Falling Asleep of Mary - but they also hold to her glorification and her bodily assumption after death. But I could be wrong on that. I'm pretty sure, though, that the Romans say she did not die.
gms+