Kind of looks like the full page view of the Today View, but without the time/date or any widgets showing. It should be located to the left of the first home screen. All you should have to do to dismiss it is swipe the screen to the left.
It’s normal. Try going to Edit and add a few widgets to see if it works the way it should.
There is no way to completely remove the Today View. You can either have it as an extra screen to the left of the main home screen, or it can be a panel on the main home screen; permanent or sliding in/out from the left.
The controls are in Settings > Home Screen & Dock. It’s the More and Bigger option at the top. And no, you can’t unpair those choices. More (smaller) icons gives you the side panel. Bigger makes it a full screen to the left of the main home screen.
P.S. The blurry effect is similar to the blur effect you get when pulling down the search screen. It’s meant to make it look like the new screen is sitting on top of the home screen on a semi-transparent layer.