The issue of writing private keys or seed words on paper has taught me a big lesson that I can't forget easily. I lost all my tokens because of that, now I can't find where I kept my private keys. It happens that my phone got formatted due to steady optimization that couldn't stop. It's not about hiding your private keys, it's about keeping it where you can remember it easily
As I said earlier,
For protecting your Seed, you can use "Passphrase" which can be used as a 2FA for your wallet. In addition to a seed, there will be an extra password called Passphrase to unlock your seed. Some wallets also call this as "seed extension". Passphrase will be used as an extension to a Seed. We need to remember both of them to unlock a wallet.
I think, we can keep the Seed(will be 12 or 24 letters long) safely in a laminated paper and store it in a bank locker. And we can remember the passphrase(13th or 25th letter in a seed) in our mind. Even if the Seed is lost or stolen, they cannot open the seed without a Passphrase. This would be a good idea to store the cryptos safely in a cold storage wallet that supports this feature. Some of the wallets that supports this feature are Ledger Nano S, Trezor wallet etc.
you could have used a wallet that supports Passphrase where you need have to remember the entire Seed. You just have to remember the seed extension rather than the whole seed.
In your case, you could have kept the paper(which contain seed) in your bank locker. It would be safe to keep it in a bank locker rather than keeping at a place where you don't remember.
