The App Library does not remove other home screens. Its merely an addition to them.
It cannot be turned off or removed, but you don't ever have to use it or access it in any way if you don;t want to.
If one of your home screens is missing tap and hold on an app and choose the "Edit Home screen" option from the menu. Then tap on the .... section below the icons to bring up the Home Screen chooser. Make sure all your home screens are correctly checked. Home screens without a check mark will be hidden.
Tap on Done to complete the process.
click here ➜ Organize the Home Screen and App Library on your iPhone - Apple Support