Paper wallet.... the only safe way.
I also use a paper wallet for large amounts and put them in my bank safe.
Steel beats paper, paper is easily destroyed, write down your private key in steel
https://cryptosteel.com/If you are going to use the company that you have linked you are spending $79 minimum to engrave on a piece of steel, when that is fairly basis to do. All you have to do is go to your nearest scrap yard and buy it off them for a few dollars and write it yourself. Although, a paper wallet if stored correctly is more than enough and doesn't require any investment at all.