The main concern you have right now is that your backup scheme has a single point of failure. If your backup were lost / stolen / destroyed, then your funds are gone.

The easiest way to improve your current security model is to implement a passphrase: https://support.ledger.com/hc/en-us/articles/115005214529-How-to-set-up-a-passphrase-?docs=true

A passphrase allows you to generate an entirely new wallet using your existing seed. You'll require both the passphrase and the seedphrase to recover the wallet. This makes it more difficult for an attacker to steal your funds, as they need both elements, but on the flipside it means you also have more things to back-up.

Much like a password, the longer a passphrase is the better. 6-8 words chosen from the BIP-39 wordlist is a good strategy: https://www.blockplate.com/pages/bip-39-wordlist

An example back-up scheme would be the following:

This setup has no single points of failure. If one back-up is lost / stolen, the funds are still safe and recoverable.

It's good practice to have back-ups stored at different geographic locations you are able to access semi-regularly, although judging from your post this may not be possible. It's also good practice to store back-ups in anti-tamper packaging so you know if they have been accessed.