UA Stands for Unverified Authentic, meaning it could come from the same factory that made the original version. Almost 100% Identical.
There is little chance to pass a platform like Stockx.
Rep - Stands for a replica version by a different factory that made the original version. It would just look almost the same.
But still has flaws sneaker head would be able to notice it is fake. But still cool to wear them for daily life and if not one is going to do a close comparison check you are all good.