I think you misunderstood me because I didn't explain the threat the clear enough.

When you first format LUKS partition, it creates a master key which is used to encrypt the data. You never see it in plain text.

The password which you set, encrypts the master key.

LUKS slot contains not your password, nor hash of your password, but encrypted master key.

If you don't know the password, you cannot decrypt the master key and cannot decrypt the disk. If you know the old password, but slot was deleted, knowledge of the password doesn't give you anything because you cannot decrypt the master key since it's not in the slot anymore.

If you know old password (it was compromised or was easy to guess) and you can recover old LUKS header, you now have access to master key which encrypted by a weak password and you now can decrypt the disk.

The main concern is how to securely update the LUKS header (delete key slot) so it could be not recoverable on the modern hardware.

It doesn't matter what encryption algorithms are used or how many iterations, if LUKS header can be recovered due to specifics of modern SSD