I understand you mentioned you already performed a factory reset. Have you attempted to reset your network settings?
- From a Home screen, swipe up or down from the center of the display to access the app's screen. These instructions only apply to Standard mode and the default Home screen layout.
- Navigate Settings.
- Tap Reset network settings.
- Review the info then tap Reset Settings.
- To confirm, review the info then tap Reset.
Do you drop connections while your device is in safe mode?
Let's try putting the device in Safe mode to determine if there are external factors that cause this symptom. This step will temporarily disable all your third-party apps, but none of your personal data will be deleted. Your customization settings (Wallpaper, Themes, et cetera) will be reset to default once you exit this mode.
Please follow the steps below:
1. Turn the device off.
2. Press and hold the Power key past the model name screen.
3. When "SAMSUNG" appears on the screen, release the Power key.
4. Immediately after releasing the Power key, press and hold the Volume down key.
5. Continue to hold the Volume down key until the device finishes restarting.
6. Safe mode will display in the bottom left corner of the screen.
7. Release the Volume down key when you see Safe Mode.
8. To exit Safe Mode, restart your device.
You can also try wiping the system cache partition to see if that helps any.
- Turn off the device.
- Press and hold the Volume Up key and the Bixby key, then press and hold the Power key.
- When the Android logo displays, release all three keys.
- An 'Installing system update' message will show for 30 - 60 seconds before the Android system recovery menu options appear.
- Press the Volume down key several times to highlight wipe cache partition.
- Press the Power key to select.
- Press the Volume down key to highlight yes, them, and press the Power key to select.
- When the wipe cache partition is complete, the Reboot system now is highlighted.
- Press the Power key to restart the device.