I’m not sure if this is the same issue if your Macbook is actually shutting down, but there are known issues with Zwift crashing on Monterey. See macOS Monterey 12.0.1 Zwift crashing
I’m not sure if this is the same issue if your Macbook is actually shutting down, but there are known issues with Zwift crashing on Monterey. See macOS Monterey 12.0.1 Zwift crashing