Memorizing the seed phrase will be okay if the person is really good in memorization.
For the seed being placed on any devices/documents/websites, I think it will be good to encrypt it rather than just putting the exact same words. Still both of these will not work for everyone, so I think people should stick on how can they properly manage to store their seeds.
One day, a piece of some heavy substance that falls on the head, or an accidental but strong enough blow to the head, completely knocks out all the information about seed phrases and, in general, about one's own name. As a result, relying on one's own strength is such an occupation.
It has already been advised many times how to save your seed phrases. I think you should not invent a bicycle. Special paranoid agents can be advised to use all the methods at once in case of any catastrophe, including an alien attack.