iPhone 7+ Hacked. Pics taken and phone calls made

Pretty frighting stuff.

I did not use my phone for 24 hours. It was left in my home in a room connected to Wifi. Nobody went into this room during that time.

The phone was locked and plugged into to a wall socket.

When I picked up the phone, the first thing I noticed was that WiFi was off. (I don't remember if it was locked as I intuitively used TouchID). I then noticed some of my emails were showing as read.

Digging further I see phone calls made and attempted. Both regular calls and FaceTime calls. There were texts and emails sent to odd names. My Safari browser history showed many searches for all sorts of things including 'reset password' pages for Gmail.

Most disturbing of all, were the hundreds of photos and videos taken. As the phone was sitting on a table all the pics were of my ceiling. In the videos you can hear muffled voices.

So far, I've set the phone to airplane mode, reset any password I can think of......but seriously.....how did this happen?

The phone is fully update to the latest iOS, I'm pretty good about not visiting shady sites and use complex passwords. But even if I was not so careful, the fact that a hacker can remotely control an iPhone is pretty scary.

I spent some time looking up articles on this and everyone keeps saying how impossible this is. The iPhone is super-secure yadayada.

Yes, I will wipe my device and start over. But that's not going to prevent this? Any insight?