WhatsApp for OnePlus 7 Pro

Aggressive battery management in OxygenOS is the usual culprit. Go to Settings > Apps > WhatsApp > Battery and set it to "Don't restrict" (older builds call this "Don't optimize"). Then clear WhatsApp's cache under Settings > Apps > WhatsApp > Storage > Clear cache, and make sure both OxygenOS and WhatsApp are updated (Play Store for WhatsApp). If it still stutters, avoid using aggressive RAM-clearing/auto-clear behavior in the Recents menu so the system stops killing the app in the background. See how others solved this on Reddit

The 7 Pro uses a non-physical (software/IR) proximity sensor that can misread, leaving the screen dark after you move the phone away from your ear. Open the hidden engineering test menu by dialing *#*#808#*#*# (the OnePlus feedback/diagnostic tool), and run the proximity sensor test/calibration there. Also keep the top of the screen and any screen protector clean and bubble-free over the sensor area, since dust or a thick protector is a common cause. If misreads continue, a reboot or re-seating/replacing the screen protector often clears it. See how others solved this on Reddit

Heavy background activity from WhatsApp (and apps like Maps) keeps the CPU and 90Hz display busy, which heats the phone and burns battery. Check Settings > Battery > Battery usage to confirm WhatsApp is the offender, then restrict it via Settings > Apps > WhatsApp > Battery > Background restriction. While troubleshooting you can drop the screen to 60Hz under Settings > Display > Screen refresh rate and disable Always-on display. Also clear WhatsApp's cache; if it keeps burning even when idle, reinstall WhatsApp to reset a stuck background process. See how others solved this on Reddit

OxygenOS is putting WhatsApp to sleep in the background, so notifications only arrive when you manually open it. Go to Settings > Apps > WhatsApp > Battery and choose "Don't restrict" ("Don't optimize" on older builds), and make sure "Sleep standby optimization" / "Deep optimization" under Settings > Battery is not freezing the app. Then open the Recents screen, find WhatsApp, and tap the lock icon to keep it from being cleared. Confirm WhatsApp's notifications are enabled under Settings > Apps > WhatsApp > Notifications. See how others solved this on Reddit

This is a notification-channel setting rather than a system bug. Go to Settings > Apps > WhatsApp > Notifications, open the "Messages" channel, and make sure "Pop on screen" (floating notification) and "Sound" are enabled and the importance is set high. Inside WhatsApp, check Settings > Notifications and confirm "High priority notifications" is on for messages. If banners still don't show, toggle the channel off and back on, or clear WhatsApp's cache to reset the notification behavior. See how others solved this on Reddit

If changing the tone inside WhatsApp does nothing, it's because on modern Android the sound is controlled by the system notification channel, not just WhatsApp's in-app setting. Go to Settings > Apps > WhatsApp > Notifications > Messages, tap "Sound," and pick your tone there. You can still set it inside WhatsApp via Settings > Notifications > Notification tone, but the Android channel takes priority, so changing it in system Settings is what actually sticks. See how others solved this on Reddit