What I do is Backup my device with Smart Switch & If you're going to Factory Reset, keep in mind that EVERYTHING stored on the internal storage will be wiped, that includes photos, documents, everything!
So although Smart Switch SHOULD be able to restore everything after you Factory Reset, if there's some stuff that you ABSOLUTELY need to make sure you don't lose, copy it or move it to the external sd card (if you have one), Or copy it to your computer, Cloud account etc.
You can Factory Reset from Settings, but I prefer to Factory Reset from Recovery.
Power Off your device & wait a few seconds, then Press & HOLD the Power & Volume UP buttons until you feel the phone vibrate, Release both buttons at the same time & you'll see the Recovery Menu in a second or so.
Use the Volume button to Scroll down to Factory Reset & Select with the Power button, Wait until the Recovery Menu defaults back to "Reboot system" & the phone will Boot back to the Welcome screen.
⚠️Know ALL your passwords BEFORE you Factory Reset ⚠️