I've taken steps to secure my Linux:

* Using Yubikey PAM always as a 2FA for ssh,sudo (also on every Linux in my home network).

* Always require authentication on each sudo command (prevents escalating once and then reusing privileges).

* Only running Docker with sudo as recommended (requires 2FA now).

* Closing all traffic other than services I need with nftables.

Regularly look at the journalctl for suspicious activity.