Just a thought: you could add a "canary": a very simple unencrypted paper wallet with private key QR-code and instructions how to claim it. If someone finds it, you lose the small amount, but you'll know your backup is compromised without driving into the desert to check and digging a hole at N34 59 20, W106 36 52 each time.
And you can connect the address to a bot on Telegram, for example, that would notify you as soon as there is movement on said address. Since the amount is an insignificant one, you don't have to worry about your privacy. The Telegram account can be connected to a phone number not used for anything else or only for unimportant stuff non identity-revealing activities.