Steps
- Open Android Settings > Battery (Battery and device care).
- Tap Background usage limits.
- Open Sleeping apps and remove Notification Tracker if it is there.
- Open Deep sleeping apps and remove it there too.
- Turn Put unused apps to sleep off if you want to be sure.
- Open Notification Tracker, go to Settings > General Settings, and check Background activity shows Allowed.
Tip
Menu names change a little between One UI versions. Search for "sleeping apps" in Android Settings if you can't find it.