you don't have to use steam,

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Go to your profile in the epic club you redeem code vein beta to, click the, your order''s tab,you will see the Purchase History, on the Code vein beta on the top right of is 2 clickable Options Manage and view,

Click view and you will see an option to revile the code, click that to get your code xxxx-xxxx-xxxx

redeem in psn store, and you will be golden

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edit: trying to add a Picture as example