Realme

System restrictions on realme phones have not been fully uncovered yet. If you have any additional information, please let us know.

Basic setting

Luckily, the system restrictions are all gathered at one place in the system settings in Battery section, and also have some description there.

Power saving mode - reduces screen brightness, changes auto screen-off time to 15s and disables background sync.
Can be set to launch automatically at a set battery level.
It may terminate background processes.
Super power sawing mode - extra saving option, allows you to have at most 6 apps to use.
It will disrupt background processes.

1. Open app battery management
> Choose Pomodoro app

2. Allow the above options.

Sleep stand-by optimization - automatically enables low power mode when the system thinks you are asleep.

1. Battery > Power saver options

2. Stand-by optimization

High-performance - consumes more power, mode for online gaming for example
Smart Performance Mode - optimized mode depending on the workload, may break background processes
No Performance Improvement - no additional boost of performance

1. Battery > Performance mode

2. Choose No Performance Improvement

Casts a ‘freeze’ spell the apps from this list - they cannot receive or send notifications and cannot run on the background.

Source: dontkillmyapp