Samsung
Optimize Battery Usage for Apps auf Samsung
Samsung's One UI includes a battery management layer that puts apps to sleep whenever they are not actively in use. The system decides on its own which apps get restricted, and it does not always distinguish between apps you open rarely and apps you rely on for messaging, fitness tracking, or calendar sync.
When an app is marked as optimized, the background processes are paused after a short period of inactivity. That is why notifications sometimes arrive late, alarms fail to trigger, or a fitness tracker stops logging steps once you switch away from it.
You can review and adjust this behavior for every installed app in one place. Open Settings ➔ Apps, open the menu icon and tap Special access, then select Optimize battery usage.
This screen only shows apps currently affected. Open the menu again and choose Select All to see the complete list, then turn individual apps on or off to control whether One UI is allowed to restrict them in the background.
Leave optimization turned on for apps you open only occasionally. Disabling it for every app increases background activity and can shorten battery life noticeably, so apply the change only to the apps that actually need reliable background access.