SSH + 2FAAuthentication
Just some sshd links. article to be written once tested
Links
https://blog.sap-press.com/securing-linux-using-2fa-with-google-authenticator
https://discussion.fedoraproject.org/t/how-to-set-up-2fa-for-user-login/82433
https://discussion.fedoraproject.org/t/2fa-code-to-login-on-fedora-desktop/87954
https://serverfault.com/questions/518802/two-factor-ssh-authentication-on-external-address-only