Greetings! After checking it appears that you have set your Stadia account as the main platform of your Cross Save setup, this is why you are asked to make a new character when you log in because that platform probably had no Destiny 2 progress. Unfortunately, your Steam characters are not able to be used at this time because Cross Save cannot be deactivated. You'll have to wait the remaining 45 days out before you can deactivate Cross Save; this wait is also [u]unable[/u] to be forcefully removed, as mentioned in a reply to a [url=https://www.bungie.net/en/Forums/Post/261011436?sort=0&page=0]previous thread you made[/url].