What happened was, I had a fully stable 16" M1 Macbook Pro, bricked it, and ended up with an OS I didn't want.

A tale as old as time, you're now older and less enthusiastic about tinkering. Stability replaces the urge to upgrade to bleeding edge. There's something to be said about "just works".

True to form in fine risk aversion mode, there I was still on Monterey. With Sonoma just coming out thought it was safe to be "Captain 12 months ago" and install the latest Ventura with all the kinks worked out. Made a Time Machine backup of current, started the upgrade, and walked away.

Came back 20 mins later to see how much time was left. Completely black screen. Weird. Hit a few keys and used the trackpad to wake it up. Nothing, system had powered off. Hitting the power button displayed the apple logo as expected, but then it powered itself off again.

Had that sinking feeling in the pit of my stomach. Made the decision to just restore from the backup I'd just made. Nervously powered it back on holding down the power key to boot into recovery mode. No recovery mode.

Fun!

A spot of light googling commenced and the internets told me that I was indeed fucked. But there was a path back to glory if you have another Mac.

Connect two Macs together via USB-C. On the working Mac, install Apple Configurator. Power cycle the bricked Mac and do the "hold down various keys for various amounts of seconds" dance to force it into DFU mode. Inside Apple Configurator on the working Mac, choose 'Revive Mac'. This will download and reinstall the recovery toolset on the bricked Mac.

That worked. Which now allowed me to boot into the recovery options on the "no longer bricked but still hosed" Mac. Yay, there's now an option to restore from backup. Chose that. Nope. Wouldn't let me do that. Instead, Apple sayeth reinstall MacOS from scratch and migrate your apps and user data from your backup using Migration Assistant. Ugh, sure, I guess?

And which OS was the only option? Of course, Sonoma. Which I had no intention of installing and absolutely did not want. But, when you're already dead in the water, just pull the trigger. So I did, let that churn for a bit. Booted into Sonoma, and assumed it would be the vanilla OS and I'd have to now try to recover all my actual stuff. But no, oh look happy day, everything is already there. And it all just works.

I saw that Sunday afternoon going differently in my mind. And no, I'm never upgrading OS again.