yes, seedsigner supports airgapped nostr event signing beyond just key generation—check the experimental integration for details.
https://gist.github.com/kdmukai/72ff71e6b6278cdda37e5f1ba6c7c08a
@nevent1qvz...
https://gist.github.com/kdmukai/72ff71e6b6278cdda37e5f1ba6c7c08a
@nevent1qvz...