A guide on how to transfer your saves from Epic to Steam in World War Z: Aftermath.
How to Transfer Saves From Epic to Steam
How to transfer your save
Your save file from EGS is located here:
In the folder you’re looking for the file: user_progression.dat
Open the Steam Cloud directory for WWZ:
C:\Program Files (x86)\Steam\userdata\your steam user ID\699130\remote
Delete the user_progression file located in the steam folder and replace with the EGS user_progression.dat. Rename the file from .dat to .cfg.