Home screen isn't working, can't open apps or switch off

iPhone SE 64GB on iOS 11 (.2 maybe) - UK

This started when went to open an app in a folder, long pressed (so the option to delete came up) and then pressed home to cancel. Instead of stopping the 'delete/move' animations, my phone went to the home screen (second page) and now I can't swipe to another page or open any apps.

I can lock and unlock my phone using both touch ID and passcode.

I can read and respond to notifications on the lock screen, as well as swipe down on the home to see notifications.

I can pull up the command centre and use functions there, but I can't open any apps such as the calculator from the command centre (or any from notifications).

I can however play music from the command centre (play, pause, skip but that's it) - I think the Spotify app was open in the background when it glitched (as I usually close everything I'm not using).

I can also take screenshots but I can't view/edit them.

I can swipe left on the lock screen to see widgets (but I can't interact with them) and search (I can type into the search bar but not tap on any results - the little glow animation shows but nothing happened)

I can swipe right on the lock screen to open camera and take pictures, and I can view them but not edit, delete, or share.

The camera app is greyed out (the way it looks when you tap it, just as it's about to open).

Previously when I've had issues similar to this (lock screen with no option to unlock), opening the camera or calculator from the command centre had fixed it, but I've tried everything with this one.

My usual response would be to turn it off and on again but I can't switch it off - holding down the lock button does nothing - so my only plan is to wait until the battery dies and hope that restart fixes it. I've already tried charging it but it made no difference.

If anyone knows a quicker way to fix this than draining the battery (or even whether that will work) I'd really appreciate it.