Some users didn't find MacOS Monterey's launch smooth. 9to5Mac reports that Apple informed Rene Ritchie, a YouTuber, that it had fixed a bug in the firmware that prevented some Macs equipped with T2 security chips starting. Upgraders who have installed Monterey will receive the latest firmware along with the OS. Most Macs manufactured between 2018 and 2020 have the T2 chip.
Apple did not specify which systems are most at risk. Apple did say that the problem was only experienced by a small percentage of users.
There is no way to repair a Mac that has been bricked by the update. Apple technical support will be able to assist you if you have any problems. Although it is not yet clear whether your Mac will need to be sent in for service, it is safe to assume that this could affect your Monterey experience. They're not as common as OS launch bugs, but they're rarely this serious.