I’ve been playing BL3 for nearly a year but I don’t have any of the additional DLC packs. I was recently given BL3 ultimate edition as a gift but I’m not sure how I can add/unlock all 4 DLCs and Season Pass 1 on my existing game and maintain all my save data and characters.
I originally bought BL3 through the Epic Game Store and the Ultimate Edt key is also for Epic Games
Go to epic games library, go to borderlands 3, toggle the settings menu and chose “manage add-ons”. Then just enable the dlcs you want (might as well enable all of them at once). Then they should download, or you may have to launch the game in order to start the download.
Also, I should note that you won’t lose anything from your saves, but if you really are worried you can backup your save from
C:\Users<your user name>\Documents\My Games\Borderlands 3\Saved\SaveGames
which I would recomend as a habit since there are rare but existing cases of people who drop an item and it falls under the map so a save backup is a good failsafe.
Oh and also keep in mind that you might need a decent amount of space in your disc in order to install the dlcs. And I think the minimum requirement is a little bit above 50 gb no matter the size of what you want to install.