Unfortunately a race to the bottom is a bad thing, not an excuse

My network security requirements have nothing to do with iOS. Can't we just collectively drop OS tribalism?

Or any other operating system...

For windows you go into the firewall settings and either set a deny rule for a specific executable or even set the default behavior to deny.

For linux there's a couple ways of setting up a process group that can't access your network.

I'm not very familiar with other OSes.

Why do you ask? Isolation between processes can be difficult on non-phone operating systems, but removing permissions tends to be quite easy.

Third party app firewalls exist for at least macOS and Linux distros. It’s likely built in to the system as well, but you’d have to wrangle the command to do it in the terminal.

They also exist for Android, for that matter.

Depending on how blur you draw the line of os:

docker run --network none