Can't unlink ea account from my steam

I want to unlink an old account from my steam and link this one instead, but I'm unable to. It doesn't even show my currently connected steam account on the "Connected Accounts" tab which I don't understand because it clearly is connected to it

Obviously, I'm able to read the last part, but I have also read from many users that it actually is possible to unlink your steam account. I'm quite confused about this and would be glad about any help. (I can't even remember why I connected my steam to that one old account tbh)