Hi Swadesh ,
Looking at paramters you provided , only paramter change which can help here is em/initial_size_MB which is set to 4 GB , it is too low . if your DB also resides on same server i will ask to divide memory between DB and SAP . intially you can increse it up to 15 GB as of now to look how SAP behaves ( will reduce the Priv mode of Dialog ) . you can check more information of this paramter in RZ11 and then increase this paramter value more if needed .
Hope this helps .
Thanks
Manas Behra