I want to say, “When will major companies learn!? Air-gap your most important Intellectual Property!”
Avoids theft and denial of access to it.
Closed source code crucial to the future of the company, should not be addressable outside of the company. And only key internal staff should have the physical and logical ability to create encrypted backups, as a part of their job requirements.
No Internet connected servers, no WiFi, no Bluetooth, no wireless keyboard or pointing devices, no USB access.
But then... COVID-19 threw a massive spanner into the works. :(
So the next best thing, NetSec with extensive defence-in-depth, minimum privs across the board, move fast on updates, encrypted data at rest and in flight, etc.