Samsung
Turn On/Off Bedtime Mode auf Samsung
Bedtime mode on Samsung phones is part of Digital Wellbeing. It grays out the screen and holds back notifications during a set time window, which is different from Do Not Disturb, that only silences alerts without changing the display or working on a fixed schedule.
Held notifications are not lost. They arrive as a batch once the scheduled Bedtime period ends, which is why a phone can look inactive for hours even though messages were coming in the whole time.
To manage it, go to Settings ➔ Digital Wellbeing and parental controls ➔ Bedtime mode. From there you can enable or disable Turn on as scheduled, and set the specific Days and Schedule that should trigger it automatically.
If you only need a quick, temporary silence for a meeting or a nap, Do Not Disturb is the better tool since it does not touch the screen and turns off instantly. Bedtime mode is meant for a recurring routine, like a nightly wind-down, rather than a one-off interruption.
Side effect to know: since the screen dims and notifications pause together, apps that rely on instant alerts, like ride-share or delivery tracking, will also go quiet until the schedule ends.