There's a couple things to address here. First, to enable cross save, you have to be able to authenticate each linked account, which means at some point, you knew the information for that account, or you wouldn't have been able to link it. Second, it doesn't matter what Steam account you have linked, because you chose Xbox as your primary account, which means that on all linked platforms, you will see your Xbox characters and game progress. If you want to switch which account is your primary account, you can use the contact form at the bottom of [url=https://www.bungie.net/en/Help/Troubleshoot?oid=48099]this page[/url], and request that your primary account be changed. If however, that really is the wrong Steam account, and you want Steam to be your primary account, you will have to work with Steam support to recover that account, and then you will have to switch the Steam account from the one you have linked to the one you want linked. A linked platform account cannot be changed to another account from the same platform while cross save is active, so you would first have to turn off cross save, which will trigger a 90-day cooldown before you can turn cross save back on, then you can change your linked Steam account, and once the 90 days is up, turn cross save back on with Steam as your primary account.