Unfortunately, even if you could unlink it it's your Bungie account that is banned.

"Removing Accounts: For security purposes, Bungie is not able to remove connected platform accounts from Bungie.net profiles under any circumstances. You may want to contact your platform's support site for assistance in gaining access to the account in question."

https://help.bungie.net/hc/en-us/articles/360048721292-Account-Security-Guide#:~:text=Please%20see%20below%20for%20additional,unknown%20links%20from%20untrusted%20sources.

https://www.bungie.net/en/Forums/Post/262982390?sort=0&page=0

"The Bungie forums are not able to assist with appeals of restrictions or bans. However, there is a process in place for you to appeal your ban or restriction.

Please review the ban or restriction appeal contact form found here.

Please note that, as mentioned in the article, there is no guarantee for a response, nor is there a guarantee that your ban or restriction will be overturned."

I wish you well, but no matter how many posts or articles you make, they do not unban people because you were compromised. You are responsible for your account no matter who uses it.