One solution to the problems you mentioned is to make multiple copies and store them in different safe places.

To solve the problem of getting wet and fading, you can laminate the papers, which is a guarantee of solving most of these problems.

To solve the problem of getting burned in a fire, you can store your papers in a fireproof box. I think if you take these steps, you can get rid of the problem of getting burned, getting wet or fading.

For extra security, you can store a copy of your wallet's private key in a bank's safety deposit box. This way, you can reduce the chances of theft or robbery.