Based on our tests in June of 2022, the alarms were inconsistent after the Macbook went to sleep. Therefore, it isn't a great idea to let your Macbook fall asleep while waiting on an important alarm. It's for this reason we don't recommend manually putting your Macbook to sleep or closing the lid with an active alarm. But, letting the Macbook fall asleep also produced inconsistent results. However, you can change the settings on your Macbook to keep your system awake longer. Head over to System Preferences and click on Battery. In the new menu, use the slider to increase the time your Macbooks stays awake. You can even select Never to keep it awake. Do keep in mind if you choose to keep your Macbook awake for long periods of time you'll need to leave it plugged in or risk the battery dying before your alarm sounds.