Borderlands 3 has much to offer beyond the main campaign, giving you plenty to do even after you complete the game's main story. Exploring the wastelands to discover missed environments, finding skipped collectibles, and taking on the various DLC are just a few of your options once the credits roll. The expansive world gives you a lot to do, but only if you are willing to search for additional content.
https://screenrant.com/boarderlands-3-post-game-activities-beat-game/