Step 1: Finish the Campaign / Complete all Side Missions.
Your first step towards achieving the Borderlands 3 Platinum Trophy or the Max Gamerscore is to playthrough the main story on any difficulty you like, whilst taking on any Side Missions you may come across.
Luckily for you there isn't any missable Trophies/Achievements within Borderlands 3 as you'll be able to go back through all the areas and accept any unfinished Side Missions or Zone Challenges at any point in the game.
Throughout your playthrough of Borderlands 3 you'll notice some Side Missions will pop up in Sanctuary that require you to kill a certain enemy, for example Kill Wick and Warty, but you don't need to complete these as they are not required for the Trophy/Achievement.
Step 2: Collect all Collectibles / Discover All Locations
Once you've completed the Main Story and finished all Side Missions you'll need to go back through all the previous areas in the game to pick up any collectibles or discover any locations that you may of missed or were unable to get at the time due to not having the correct equipment.
Refer to the Full Area Coverage section of the guide to get an indepth guide on how to get every collectible in the game alongside where to find the locations.
Step 3: Circles of Slaughter / Eridian Proving Grounds
Once you've fully completed the story you'll gain access to three Circles of Slaughter and six Eridian Proving Grounds which are the endgame of Borderlands 3. You'll need to complete all of these to get their Trophies/Achievements, aswell as finishing of the Side Missions Trophy/Achievement.
Check the following sections of the guide for more information on how to complete these endgame activities.
- Circles of Slaughter
- Eridian Proving Grounds