Bungie doesn't have any account services so it is not possible for a "Bungie account" to get hacked. Bungie profiles are secured via your platform account. So if someone was able to add or change linked accounts on your Bungie profile they did so by gaining access to one of your platform accounts. So if anything was hacked it was a PSN, XBox, Stadia or Steam account. To prevent further unauthorized access you need to change the passwords to all your platform accounts and make sure two factor authentication has been enabled. Also, most 2FA systems allow you to see what has been authorized along with the ability to revoke the authorization. If the platform accounts in question have this ability I would suggest revoking all logged access. If the Steam account that is linked to your profile belongs to another person then it will be impossible to remove it from this profile. In that instance your only choice is to abandon this Bungie profile and move your good accounts to a new Bungie profile. Keep in mind that game progress is stored on your platform account, not a Bungie profile, so moving to a new Bungie profile does not wipe or change your existing game progress and characters. With that said, if there are any emblem codes you've redeemed in the past on this profile, you would lose access to those when you move your platform accounts to a new profile.