I started a new campaign, but the game is still listing all the achievements as being completed. I'd like to try them again (and have the game keep track of which ones I've done). This is the only thing I'm actively looking to clear, but there's nothing I particularly want to keep so I don't care if I wipe anything else and start fresh there too.
You can not reset your achivements, they are saved to your account on the region.
You have two options:
- Go to another region and play, this should show the achivments that you have gotten in that region. This is limited by the number of regions you have the game in.
- Make a new account with a new game. This will require you to buy a new game.
Best option, instead of buying another copy (if you don't mind not having the record keep track online), play Offline Mode after deleting your saves.
This should reset all tracked progress and give you that "fresh start" feel.