How do I create a SECURE ad hoc network?

Well... I'm posting this question with the same subject title as an older one because that was where I wound up when I had the exact same problem today and, after hours of tearing my hair out trying to solve it with the "best answer" there , I stumbled upon the correct answer. So this is for my fellow veteran Mac users who will find their way here from Google. (But only if they get to the point of finding out what an "ad hoc network" is!)

The ingredients for this problem:

One Apple Airport Express 2nd gen

(that's died with a steady amber light and won't appear anywhere you look)

or any other WiFi router that's suddenly left you helpless.

One M1 Mac Mini 1st gen

(Running Monterey 12.7.1 because I can't afford to replace my MOTU 828 Firewire audio interface), and

One iPhone 11.

Throw in a couple of Apple TV boxes if you've got 'em.

So... the Airport dies, leaving me with a crappy cell phone connection at home and no network to connect my Apple TVs to.

Like the poster of the original question I remembered once setting up a secure (WPA3/WPA3) network on a desktop Mac which is connected to the cable modem via Ethernet cable.

By the time you read this you've probably jumped thru the same hoops I did in even trying to find the User Guide for OS Monterey. (Right... it IS on the Apple website but you won't find it unless you search google.)

Then you get to create an ad hoc network via the WiFi menu that specifically tells you "this is an unsecured network". For you younger folks, this used to be the way you did it; you hosted the network and then you could share your connection or whatever else you wanted to do.

Anyway, the correct answer is not to create a network; just go to System Preferences > Sharing and share your internet connection and the system sets up the secured network for you. Simple, safe and secure.

I was already at the point of setting up a hotspot on my phone and trying to connect the TV to that, which of course was a dismal failure. But, in the course of making sure I wasn't leaving my unsecured network door open too wide, I found the answer. Works great. The TV is maybe 40 feet away through 4 apartment walls, but the signal is just enough to stream Netflix or YouTube.

So all you point collectors out there: make note of this. You can probably find a couple of places to apply this knowledge now that you have it and pick up a few extra points.

Since I can't award myself the best answer prize, it'll go to the funniest explanation for why Apple "improved" the existing situation by letting you easily set up a temporary insecure WiFi network that's basically useless.

Cheers