Unfortunately, that will not be done. You can talk to Valve for Steam about removing any licenses you own. The save data that your Steam ID points to, though, will not be completely wiped. You can delete your characters yourself, but your Collections, Triumphs, and the like will still be there. If you want to start entirely and completely fresh, you have two options. 1) Create a new Steam account and go from there. 2) Create (or use) an Xbox account or a Playstation account and then link that to your Bungie.net profile. Then, use Cross-Save and make sure you select that account as your main Cross-Save data. Then, when you log in on Steam, you'll be using the save data from that account. If you've never played Destiny 2 on the account you choose, then it will be entirely fresh.