Write your seed on paper or punched metal.
This ensures you can recover your wallet with a different device but not how to protect your existing one from the threat of EMPs.
If your device gets destroyed by an EMP, in all likelihood all the electronic communications in your immediate environment will also be wiped out, so it wouldn't matter if you had an EMP ruggedized hardware wallet to begin with.
You have bigger problems that not being able to move your bitcoin.
That's fine, but while those problems are going on I want to protect the one device that allows me to move money easily.