There's fiatjaf's nos2x plugin which works well. https://github.com/fiatjaf/nos2x You can put your own nsec/pk in there. Signing messasges from a hardware wallet would be a bit of a manual chore, but you could do it if you know how to format and broadcast a raw nostr note. Trezor can sign arbitrary data: https://trezor.io/learn/a/sign-verify