Honestly I think Trezor is fine, but unnecessary.
My personal method of choice is distributed (copies of) BIP38 encrypted paper wallets, costs next to nothing (just the price of the paper), and these encrypted keys can also be safely stored on digital devices as well for redundancy as they are encrypted and safe as long as your password is strong.
I think you're being a bit paranoid with your printer tbh, I mean it never hurts to be safe but the chances of your printer being compromised are really next to nil.