Steam-linked account: cannot reset password / old password unknown

I play Path of Exile 2 through Steam and would like to use the standalone client.

My Steam account is connected to my Path of Exile account, and my account page also shows that a primary email address is already set.

The problem is that I do not know the old Path of Exile password. When I go to “Change Password”, the website asks me to enter my current/old password first, which I do not have because I normally log in through Steam.

I then tried using the password reset option by email. I receive the password reset email, but when I click the reset link, the website only shows:

“Resource Not Found – The resource you are looking for does not exist or has been removed.”

I do not want to delete, unlink, merge, or accidentally connect the wrong account, because I do not want to risk losing access to my characters, purchases, or Steam-linked account.

Is there a safe way to set or reset a standalone email/password login for an account that is already linked to Steam, or should this only be handled by GGG Support?

Thanks in advance.