WhatsApp for Nord 3

OxygenOS won't show full-screen incoming-call notifications over the lock screen unless WhatsApp is fully permitted. Go to Settings > Apps > App management > WhatsApp > Notifications and make sure Allow notifications and the Calls channel are on. Then open Settings > Apps > Special app access > Display over other apps and enable it for WhatsApp so calls can appear over the lock screen. Finally, go to Settings > Battery > More settings (or Settings > Apps > App management > WhatsApp > Battery usage) and set WhatsApp to Allow background activity / Don't optimize, so the system can wake the screen for an incoming call. See how others solved this on Reddit

OxygenOS App Cloner runs the second instance under a separate Android user profile, so its data lives in a sandboxed path (typically Internal storage > Android > data or a numbered /999/ user folder) that the normal File Manager can't fully browse. The reliable way to get media out is from inside the cloned app: open the cloned WhatsApp, go to Settings > Chats > Chat backup to back up, or open a chat and use Share / Save to export specific photos and videos to your gallery. You can also enable Show hidden files in the File Manager menu and check Android/media/com.whatsapp, but newer Android storage scoping often hides the cloned copy, so exporting from within the app is the safest method. See how others solved this on Reddit

After a system update WhatsApp can lose its notification and background permissions, so messages and calls stop arriving until you open the app. First go to Settings > Apps > App management > WhatsApp > Storage usage > Clear cache (do not clear data, which would wipe chats). Then re-grant permissions: under Notifications turn everything back on, and under Settings > Apps > Special app access > Display over other apps enable WhatsApp. Re-enable Autostart for WhatsApp (Settings > Apps > App management > WhatsApp > Autostart, or the Auto-launch toggle), update WhatsApp from the Play Store, and set WhatsApp to Allow background activity in its Battery settings so the updated power rules don't kill it. See how others solved this on Reddit

WhatsApp's official iPhone-to-Android transfer is done through the Move to Android app during the Nord 3's initial setup, and it needs a USB-C to Lightning cable. Start setting up the Nord 3 (or factory reset and start over), install or open WhatsApp on the Android side when prompted, connect the cable, and on the iPhone open WhatsApp > Settings > Chats > Move Chats to Android, then scan the QR code shown on the Nord 3 to copy your chats and media. This must run as part of setup and the same phone number must be used. An iCloud WhatsApp backup cannot be restored directly on Android, so without the cable transfer your old chats won't carry over and only new Google Drive backups will be available going forward. See how others solved this on Reddit

This is OxygenOS aggressively closing WhatsApp in the background. Go to Settings > Apps > App management > WhatsApp > Battery usage (or Settings > Battery) and set it to Allow background activity / Don't optimize. Then enable Autostart (Auto-launch) for WhatsApp under Settings > Apps > App management > WhatsApp so it can wake to receive calls. Finally, open the Recent apps switcher, tap WhatsApp's icon at the top of its card and choose Lock so the system keeps it in memory instead of clearing it. See how others solved this on Reddit