You can use software that allows you to create a wallet with a seed phrase of 12 words.
It's not impossible to remember 12 words if they are very important. This way you can keep the wallet in your brain. Also known as a bitcoin brainwallet. No one can steal your thoughts.
In cryptography we trust (& verify).
I have considered a 'brainwallet' before but I think the key is to refresh those words regularly
as in to make sure you are remembering the correct words.
In the case of war where you have to vacate you home or that you cannot actually get to
your home a brainwallet is the only thing which is going to save you.
Another idea is if possible create your own seed phrase from a favourite book, say
the last 12 words in the last sentence of the last chapter, all you have to do is remember
which book.
If you create your wallet in a secure machine with open source software using an open operating system like GNU/Linux (better also to be done offline), there's no need to worry. You can keep your coins at your address for years. The only time to worry about moving the coins would be if bitcoin potentially needs a quantum resistance upgrade. You don't actually need to move your coins constantly. Cryptography of BTC isn't known to be broken and so long as that remains true an address whose private key was created securely has no need to stop being used to store coins.