iPhone keeps on restarting after unlocking

Try a forced restart of you device:

Press and hold both the Power (Side) and the Home buttons for at least 10-15 seconds, until you see the Apple Logo. When it appears, release both buttons, wait for your iP6s+ to restart, then test it.

Take a look also at your battery status: Settings>Battery>Battery health (Beta).. tap on it and read the maximum capacity percentage. If it is less then 85%, it is close to the end of its life, and I suggest that you have it replaced at your most convenient Apple Store or AASP: Apple - Find Locations - Location Selector

Regards

Giulio

Restore iOS using iTunes. The Restore process will first make a backup, but you want to check "Encrypt backup" if you want all of your personal information restored. Do not forget the backup encryption passcode!

I was just writing the same procedure, Larry.

You're faster than light. How many coffees have you drunk? 😮

Giulio

One, but it was a really big one 😉

I'll do the same. A big one could be better than two 😁.

As you know, when you come and assist me, it's always a pleasure.

Have a nice day.

Giulio