How do I get rid of App Library. So annoying.i had apps where I wanted them.

you're not talking to Apple here.

If you want to leave them feedback you can do so here

Are you sure you didn't hide your Home Screen pages?

At least one Home Screen that is not your App Library has to be present..

On that screen, tap and hold on the screen somewhere (not on an app) until stuff wiggles

Tap on the dots right above the dock. see if there are unchecked screens shown there

pulling apps out from the library is pretty easy..

From your Home Screen, swipe left until you get to the App Library.

Swipe downward and you'll get an alphabetical list of your apps.

Locate the app in the list or type the app name into the search field

Once you've located the app, tap/hold until it raises/selects, then drag it and it'll pop out to your Home Screen

Organize the Home Screen and App Library on your iPhone - Apple Support

you cannot get rid of the App Library..

The presence of the App Library does not change where you had your apps, it's just another screen on the far right.

Move an app from the App Library to the Home Screen

You can add an app in the App Library to the Home Screen, unless it’s already there.

Touch and hold the app, then tap Add to Home Screen (available only if the app isn’t already on the Home Screen).

The app appears on the Home Screen and in the App Library.

I can't tell you why 'it' happened or what Apple expects.

Did you check if your Home Screens were hidden like I suggested checking?