Air gapped?
Try nostr:npub1s0vtkgej33n7ec4d7ycxmwt78up8hpfa30d0yfksrshq7t82mchqynpq6j Passport / Core.
Easy to setup, easy to use. Open-source, airgapped. Don’t leave them on a hot wallet or exchange please, and make a proper backup in steel.
Discussion
As in it has no connection with internet or internet connected devices. If you want to sign a message it happens encrypted via qr codes you’d need to scan with the software your using.