Hi evixu,
The greyed-out Unlink button usually means the PlayStation account isn’t currently eligible to be unlinked, such as during the account-linking waiting period.
Please review the unlinking rules and risks here:
Unlink your platform account from your EA Account
Keep in mind that progress and content remain with the EA Account where they were earned and won’t transfer to another EA Account after unlinking.
We can’t remove the link from the forums. Select Contact us at the bottom of the guide for help checking the available options. If live chat hasn’t helped, you can also use the webform.
I hope they can help clarify when the account will become eligible for unlinking.