WhatsApp for Nord 2T

OxygenOS aggressively battery-optimizes WhatsApp, which kills its background connection. Go to Settings > Apps > App management > WhatsApp > Battery usage and set it to "Don't restrict" (allow background activity), and enable "Allow auto launch" so WhatsApp can run in the background. Then under Settings > Battery turn off "Sleep standby optimisation". Finally confirm notifications are fully enabled under Settings > Apps > App management > WhatsApp > Notifications. See how others solved this on Reddit

This is the same OxygenOS power-management issue: the system suspends WhatsApp's background sync when the screen is off, so messages only arrive once you reopen it. In Settings > Battery disable "Sleep standby optimisation", and in Settings > Apps > App management > WhatsApp > Battery usage choose "Don't restrict" and enable auto launch. Locking WhatsApp in the Recent apps screen (open Recents, tap the app's three-dot/menu icon, choose "Lock") helps stop it being cleared from memory. See how others solved this on Reddit

WhatsApp's built-in camera uses a simple crop that doesn't match the Nord's sensor, so previews can look stretched or off-center. As a reliable workaround, take the photo in the normal OnePlus Camera app first and then attach it via the paperclip/attachment icon > Gallery, rather than using WhatsApp's in-app camera. Keeping WhatsApp updated through the Play Store also helps, as fixes for camera framing have shipped over time. See how others solved this on Reddit

This is the proximity sensor working too eagerly: it thinks the phone is near your ear and turns the screen off so audio routes to the earpiece. To play a voice note through the loudspeaker without the screen blanking, hold the phone away from your face, or use headphones/Bluetooth. If it happens constantly, clean the area around the earpiece and front camera where the sensor sits, remove any screen protector covering it, and restart the phone. See how others solved this on Reddit

WhatsApp needs extra permissions to show a full-screen ringing UI over the lock screen. Open Settings > Apps > App management > WhatsApp > Permissions and enable "Display over other apps" (Appear on top), and make sure call notifications are allowed to show on the lock screen under WhatsApp > Notifications. Disabling battery restrictions for WhatsApp (set Battery usage to "Don't restrict") is also required, otherwise the incoming-call screen may never wake the phone. See how others solved this on Reddit

A linked WhatsApp Web/Desktop session stays connected only while WhatsApp keeps running on the phone, and OxygenOS keeps killing it in the background, breaking the desktop session. Set its battery usage to "Don't restrict" under Settings > Apps > App management > WhatsApp > Battery usage and lock WhatsApp in the Recent apps screen. If the link still drops, unlink in WhatsApp > Settings > Linked devices and re-scan the QR code fresh. See how others solved this on Reddit