WhatsApp for Samsung Galaxy S24

Samsung's aggressive battery management is almost always the cause: go to Settings > Apps > WhatsApp > Battery and set it to Unrestricted, then in Settings > Battery > Background usage limits make sure WhatsApp is NOT in the "Sleeping" or "Deep sleeping" apps list. Also turn off Settings > Battery > (3-dot menu) Automation > Auto optimize daily so the system stops force-closing apps overnight, and confirm Notifications are enabled for WhatsApp in both One UI (Settings > Apps > WhatsApp > Notifications) and inside WhatsApp > Settings > Notifications. See how others solved this on Reddit

Open Settings > Advanced features > Dual Messenger, then toggle WhatsApp on and confirm to create a second cloned instance with its own icon. The cloned copy registers as a separate install, so you verify it with a different phone number. If the second WhatsApp keeps logging out or missing notifications, give the cloned app the same Unrestricted battery setting under Settings > Apps > (cloned WhatsApp) > Battery as the original. See how others solved this on Reddit

Make sure WhatsApp has the right permissions: Settings > Apps > WhatsApp > Permissions and allow Phone, then enable Settings > Apps > WhatsApp > Appear on top so incoming calls can show full-screen. Set the battery to Unrestricted (Settings > Apps > WhatsApp > Battery), and inside WhatsApp confirm Settings > Notifications has call notifications enabled so the ringer fires even when the screen is locked. Also check that WhatsApp isn't in the Sleeping apps list under Settings > Battery > Background usage limits. See how others solved this on Reddit

No. One UI only lets you set an SMS/RCS app as the default texting app under Settings > Apps > Choose default apps > SMS app, and WhatsApp isn't an SMS app, so it can't replace Messages there. What you can do is remove the Samsung Messages or Google Messages icon from your home screen and place WhatsApp in its spot, and add a direct-chat shortcut by long-pressing a chat in WhatsApp (or long-pressing the app icon) and dragging the contact shortcut to your home screen. See how others solved this on Reddit

One UI's system haptics can override per-app vibration patterns. Go to Settings > Sounds and vibration > Vibration intensity and raise the Notification slider so the vibration is actually felt. Inside WhatsApp, set Settings > Notifications > Vibrate to Long or Default rather than Off, and check that the per-chat custom notification (long-press the chat > Mute/Custom notifications) isn't conflicting. If patterns still get flattened, it's a known One UI limitation rather than a WhatsApp bug. See how others solved this on Reddit

Android Auto only supports reading and replying to WhatsApp messages by voice, not placing or receiving WhatsApp voice calls, so calls keep ringing on the phone itself rather than routing to the car. Make sure WhatsApp is enabled in the Android Auto app settings under Customize launcher / Notifications, and that WhatsApp has Microphone permission. If message notifications also fail while driving, set WhatsApp battery usage to Unrestricted so it stays alive while connected to the car. See how others solved this on Reddit