We can individually optimize the battery consumption of each app installed on the OnePlus smartphone.
The following options are available to us, which optimally limit the use of the battery for each app:

Note: We do not recommend optimizing Messenger apps, such as WhatsApp, because incoming messages may be delayed or may not load until after the app has started.

Android 10 | OxygenOS 10.0
Step 1:  Open the  Settings
Step 2:  Tap on  Apps & notifications
Step 3:  Tap on  See all apps
Step 4:  Choose an  app
Step 5:  Tap on  Advanced
Step 6:  Tap on  Battery optimization
Step 7:  Choose  Intelligent Control ,  Optimize  or  Don´t optimize
  1. Open the Settings
  2. Tap on Apps & notifications
  3. Tap on See all apps
  4. Choose an app
  5. Tap on Advanced
  6. Tap on Battery optimization
  7. Choose Intelligent Control, Optimize or Don´t optimize

OnePlus Instructions