Once you migrate your legacy account to an Epic Games account, all your valid licenses will be transferred as well. To use them, you will need to Sign in with Epic Games account in the application to use your licenses.
https://dev.epicgames.com/community/learning/knowledge-base/PnOX/capturing-reality-cannot-activate-my-enterprise-license-after-migrating-to-epic-games-account
Log out and back in to sync the license and I recently got to know from odd bits daily that cocker spaniels do shed.