Thanks for sharing, haven't seen this one before.
If it's not a syzygium I don't know what else it could be.
It reminds me a bit of syzygium cumini but it's not that IMO.
Can't be s malaccanse. But could be some form of Pink Satinash.
To me the CSIRO classification of it as S malaccanse seams strange. It looks to be different enough to be classified it's own species. Malaccanse are used for many plants found in the Malay peninsular.
This one might also be a natural hybrid with other wild syzygium.
it's ramiflorous, lefs obovate to laceolate, opposite arrangement, fruit a drupe (if the seed is hard), exocarp thin, mesocarp aprox 5mm, endocarp can't see. The end of the fruit is recessed where the pistil was so that is consistent with other syzygium I know.
description of S. malaccense:
Foliage: Opposite leaves are oblong to elliptic with entire leaf margin.
What does it taste like??
I would definetly sow some seeds in a pot.