In App Store Connect, is there a way to tell whether a Code has been redeemed and who it was redeemed by?
How to find out if a Promo or Offer Code has been redeemed & who it was redeemed by?
No, I don't believe you can do that.
You may be able to see the total number of codes that have been redeemed by looking for sales with zero proceeds, or something.
With StoreKit transactions you can see the offer that was redeemed but not the specific unique code for customer privacy.