You are the CISO for a publicly traded company. What protections would you implement to ensure availability of your systems (and why)?

If I were the CISO for a publicly traded company, I would implement multiple cybersecurity measures to ensure the availability of systems. These measures include firewalls and 2-factor authentication. Another big solution would be to back up the systems multiple times in multiple places. By backing up the systems, if they were to go down, they would still be available because the back up can easily be found.