Ganirelix can reduce E2 levels but I don't know how much it's true for each individual person - it may vary greatly.
My E2s on ganirelix were up in the 1400's or so... so... I'm not sure. We wound up with 5 on one cycle and 6 eggs on another.
I would say that both our antagonist cycles produced the best looking embryos we ever had and I did technically get PG on both cycles.
So I know it's crushing to be keeping track of the numbers and feel dismal before a retrieval but try and keep the mentality that it's quality over quantity and your magic bean might be one of those retrieved.