NOTE: This process will only update your locally stored save files, so you will need to refresh any existing cloud saves to reflect the new files. All characters and preferences in both the Steam and Epic versions of Borderlands 3 should show up the next time you boot them up.sav files representing your Vault Hunters.) (These files include profile.sav which tracks your Options preferences and all the numbered. Copy all files from the existing platform folder and paste them into the newly created platform folder.Boot up Borderlands 3 for the first time on the destination platform (Steam or Epic) to create a unique folder associated with that platform, then exit the game completely.
Your save data can be transferred between the Steam and Epic PC platforms, but the save files will have to be moved manually. Save files are located in your local 'Documents\My Games\Borderlands 3\Saved\SaveGames\' folder, with each Steam or Epic account having its own unique identification label (a long string of numbers and letters).