By double encryption, I mean using an SSH server other than "tailscale --ssh". No one except yourself can have SSH access if you disable Tailscale's builtin SSH server, use OpenSSH, and generate your own keys for authentication.
Ah, I don't think that's exactly what this thread was about. Ignoring how authorization works, the question was whether there is an advantage to encrypting your commands again (via say ssh) vs. just sending them in plaintext under wireguard (via say rsh)