I think RNDIS started as a built-in with XP, and there's MSFT-supplied drivers (now hosted at archive.org) that cover the win9x era. Someone wrote about that here: https://thp.io/2023/rpizero-usb-win98.html . As connecting old stuff to new stuff goes, it actually looks pretty straight-forward. :)

But I've heard rumblings that Linux is dropping/has dropped RNDIS from the kernel. That's unfortunate; it may be broken and ugly, but it's useful and I like useful things. (Those interested in the uber-security can just never install the kernel module, I'd like to think.)

And I've never spent much quality time with a Mac[1]. I'm lead to believe that RNDIS is a third-party thing there.

But, sure: It's all solvable. For getting an old PC online with parts already on-hand, it might even be worth solving. The amount of fun this entails just depends on the OS. :)

[1]: I once had a stunningly-beautiful dumpster-score G4 iMac with an absolutely gorgeous 20" screen, the SuperDrive, and all the RAM. If it had any pores on its flawless exterior, then those pores would have had an effluence of unbridled sex and the most forbidden of fruits just eeking out of them like the exquisite nectar of some kind of visceral deity, and that, if consumed, would constitute such an unholy and sinful act of gustation that books would have been written about it and then transcribed and passed down generationally until the very last moment of the end of all time -- to serve as a warning to others.

It was a very special machine.

Anyway, I just wanted to use it on the bench in the garage to read auto repair manuals, browse some repair forums, and listen to music on Spotify. I couldn't get all of those things done acceptably at that time under any operating system.

Like many so many other beautiful things that ultimately turn out to be impossible to cohabitate with, it turns out that I should have just left it there in that dumpster to begin with.

And that was enough Macintosh for me. I'm over it. No idea what happened to it. With any luck, it got beaten, crushed, and set on fire before finally being buried forever in a landfill, whereafter it can never tempt anyone again.

Getting an old Computer online with Android Ethernet tethering