I have a Galaxy Note 4 with all the official updates, software. The phone is not rooted, no custom firmware. All applications are from the Play Store, no cracked or hacked apps.
Everything was running fine, for the last week or so it started to randomly get slow (for example entering the PIN code is like one number in 10 seconds), at this point nothing is working, screen stays black, and the phone restarts. This happenes couple of times, afterwards it is ok. Sometimes the phone just randomly restarts, during browsing, or playing games.
Sometimes when I get a call, the phone rings, but the screen stays black, turns on only about 7-8 seconds after the ringing starts, but then the pickup is not working. But sometimes everything is ok for hours, and then it starts again.
One other thing I have noticed is, that for the last months when the battery goes below 30%, it just simply turns off, but that could be that the battery is old.
Couple of days ago the space on the phone ran out, about 500MB were free, but I have removed 6-7 GB of data, issue remained.
The last application, that was installed before the issues started was Google Family Link, but that was removed later for troubleshooting, issue remained.
Has anyone experienced this kind of behaviour?
Is there somekind of diagnostics tool, that I can try out?
How can I make a full backup of the whole phone, before I perform a factory reset?