There are some limitations around unlinking and relinking accounts. For instance, when you link accounts, it creates a lifetime link to protect you from malicious activity and help prevent performance issues in your games.
You should be able to unlink your platform accounts from your EA Account if you want to link them to a different EA Account, as long as that EA Account has never had the same account type linked to it before in its lifetime.
That means if you unlink an Xbox gamertag from your EA Account, you can’t link a different Xbox gamertag to it in the future.
Once you unlink a platform account from your EA Account and link it to a new one, you can’t unlink it again for six months.
As you have multiple EA accounts, please try reaching out to our Customer Support Team. It is necessary for an Advisor to review the accounts, and look into what can be done to consolidate your experience. We can't do that here on EA Forums, sorry!