I have to exact same issue. A very flawed system.
EA Help response "I would like to inform you that this is something which is not possible as as once the account got linked we do not have an option to reverese the action or make any other changes into it since you linked new SWGOH profile with EA account, there is no possibility to link it back to old SWGOH account"
My response was, "Why can't I use the mobile game app setting to unlink it from the EA Account?"
EA Help Response: "Because there is no option to unlink it, and it can't be unlinked now! As of now, there is no option to escalate this issue as there is no special queue for this as its working as intended."
So there is no way to delete or disconnect your account.