EVAsuka_3volte Is your Steam Account linked to the same EA Account as the PlayStation Account?
You can check by logging into your EA Account here: My EA Account | Sign In, using either your Steam or PlayStation Account as the sign-in method, and then going to the "Connected Accounts" tab.
If the accounts aren't linked to the same EA Account, then that would be why as your Apex progress and data is stored on a EA Account level.
Furthermore, if you had unlinked one of your platform accounts from its EA Account to then link it to the other platform account's EA Account, that also won't transfer, (or merge), your Apex progress and data since that is stored on the EA Account the platform account was unlinked from.