Hey DPSBadge1,
Sorry to hear someone else had gotten into your account. Please keep in mind that game progress is stored at the EA account level, so unlinking your Steam account may lead to missing content and progress, per the risks of unlinking.
That said, if you haven't already and are able to, it'd be best to go through as many of these security steps as possible to help get your account back under your control, and connect with our support team to try to recover the account first. An advisor will need to verify your account ownership before proceeding, but should be able to work with you to correct any changes made to the account. Once you recover the initial EA account, you can follow these steps to submit an appeal to address the account action.
Unfortunately, platform accounts cannot be unlinked while an account action is active, so if you'd rather not recover the old EA account, it'd still be best to reach out to our live support team to see if there are any other options available in this case. Thanks!