For your reference, here are more details about the sleep mode of the Redmi Watch 4:
1. When the sleep mode is on, the watch will remind you to go to bed and automatically turn on the Do Not Disturb mode and turn off the wrist-raising screen when it is time to go to bed. When it is time to wake up, the watch will sound a wake-up alarm, which is the same as the alarm set on the watch;
2. After you turn off the alarm, the watch will automatically exit the Do Not Disturb mode and turn on the wrist-raising screen;
3. For non-MIUI phones, the morning report reminder will still pop up after turning off the alarm and display the sleep time and today's weather information. MIUI phones have their own morning report for waking up, and the watch will not remind you repeatedly;
4. You can turn on the sleep mode by opening the [Mi Fitness] APP >> [Device] >> [Sleep mode] >> [Schedule] >> choose to synchronize your phone’s work and rest time (MIUI system), or customize bedtime and wakeup time (non-MIUI system), and wait for the watch to be synchronized successfully.