See: situation in Russia, China, ... What are your tips?
AFAIK, it's a common practice to have critical systems disconnected from the internet or external networks and located in rooms protected against human intrusion (duh) but also against remote sensing, which these days includes pretty much anything (RF, sound, light, etc).
You'd also need to take special measures to avoid equipment from being tampered with before it reaches you.
I read articles that the Russians were banning computers altogether in some circumstances and using typewriters instead.
But of course if this is indeed "threatening" you'd be as likely to have an 'unfortunate accident' in any case.
2.) ???
3.) Wallow in despair?
https://www.theguardian.com/world/2013/jul/11/russia-reverts... for example.
Limit admin privileges
Install an up-to-date antivirus/HIPS/EDR solution (with web protection)
Keep your OS and apps up-to-date (apply patches)
Periodically scan your system with tools like Loki, Thor Lite scanner etc.
Be careful about your browser extensions and their privileges
Make sure you don't expose any public service to internet (RDP etc.)
Try to avoid Windows (if possible)
Implement application allowlisting
Use file-integrity apps to protect critical files
Monitor continuously (via NSM and EDR), respond ASAP (isolate etc.) when you see a sus. thing on your system/network before they complete their objectives
Read about latest threats, evaluate your posture since threat landscape keeps changing
Read about threat/incident reports regarding state-level actors targeted your industry in the past