Why macOS updates might brick your Mac, and what you can do about it
https://arstechnica.com/gadgets/2021/11/why-macos-updates-might-brick-your-mac-and-what-you-can-do-about-it/
Anecdotal reports from over the weekend indicate that the macOS Monterey update may be bricking some Macs during installation, leaving the machines unresponsive. MacRumors has rounded up a representative swath of complaints from the Apple Support Communities forums and Twitter, mostly describing the same symptoms: unresponsive Macs that can't be revived using the typical SMC and NVRAM diagnostic catch-alls.
The reports rounded up by MacRumors mention multiple Intel Mac models, ranging from the 2015 model year all the way up to 2020, but don't mention Apple Silicon models—this makes some sense, since they update a bit differently than Intel Macs and may not be susceptible to the same problems.