Older Macs Are Bricking After Installing macOS Monterey, Claim Several Owners
https://wccftech.com/macos-monterey-bricking-older-macs/
If you are the owner of an older-generation Mac and installed macOS Monterey on it, only for it to stop responding, then you are not alone. No, it is not because your Mac is incompatible with Apple’s latest update, but something else is affecting these machines.
A multitude of older Mac owners are suffering from the same problem, according to MacRumors. In fact, there are at least ten separate posts on Apple Support Communities highlighting the same scenario. This bricking issue can also affect 2020 models, with one owner of the Intel-based 16-inch MacBook Pro complaining about it.