I wish to delete this account, or unlink it from everything
When I started Destiny 2, it said it was optional to make an account here to get rewards. I was led to believe this was in-game rewards, but turns out to be random merch I don't really care about. If I am reading correctly, this also means I am not required to have this account, and I could use just a Steam account to have my save data. I'd like for this account to either be deleted, or have everything, including email and Steam account, unlinked, so that I can safely ignore it, I just want to play the game without having tons of other unrelated services. It didn't allow me to unlink my Steam account (I believe it's because I created it using a Steam login), and I also couldn't outright delete it.
Create a throwaway account on Xbox or Playstation. Link that account to this profile, then log out of bungie.net and and log in using the throwaway account's credentials. Now you can go to accounts and linking in your profile and unlink your Steam account from this profile.