>>5264
>I'm interested in having an OS that simply doesn't have networking at all.
Back in the day you would install Windows and just... not install the wifi driver from the CD-ROM. :^)
On a more serious note, you could make a custom Windows ISO with as many disabled or outright removed features as you want using tools like NTLite (Windows 7, 8, 10) or nLite (Windows 2000, XP) or even 98lite (Windows 98). I've used the last two extensively years ago although I never disabled something as crucial as networking.
There's also Linux and the BSDs which, being open source, should give you the freedumbs to remove/disable any part of the OS that you do not want.