Oppo
Restrict App Data Usage auf Oppo
When an app keeps consuming mobile data in the background, ColorOS is usually just following its default permission setup: every installed app gets automatic access to both Wi-Fi and mobile data the moment it is installed. That permission lives in the app management system, not in the app itself, so you often cannot control it from the app's own settings menu.
To change it, open Settings ➔ App management ➔ App list ➔ [App you want] ➔ Data usage details. From there you can independently toggle Disable Mobile Data or Disable Wi-Fi for that single app, without touching your phone's overall network settings.
This matters for apps that sync large files, stream video, or auto-update in the background. Blocking mobile data alone still lets the app work over Wi-Fi, while disabling both cuts it off from the internet completely.
If the app misbehaves after you restrict its data access, for example a messaging app that stops sending notifications, check whether it also needs background activity allowed elsewhere in the battery settings. Disabling data usage only blocks network traffic; it does not decide whether the app is allowed to keep running in the background.