Why is my iPad keyboard undocked?

Have you enabled the Scribble feature? This feature uses a different mini-keyboard that does not respond to the two-finger zoom or pinch gestures.

Settings > Apple Pencil > Scribble - set to OFF

Otherwise, to restore the new Floating Keyboard to the normal on-screen keyboard presentation, use the two-finger “zoom” gesture (i.e., the reverse of the two-finger “pinch”).

If the Split Keyboard is restored instead of the full on-screen keyboard, you can either use two fingers (one on each of the two half-keyboards) and swipe the two halves together - or touch-and-hold the “keyboard” key, then slide your finger to the Merge & Dock option and release.

Use the floating keyboard on your iPad – Apple Support

Split and move the keyboard on your iPad – Apple Support

Touch-and-hold the “keyboard” key at bottom-right of the on-screen keyboard- then slide your finger to the Merge & Dock option and release.

Are you saying it’s not the normal floating keyboard but the one that normally sits at the bottom of the screen but is now in the middle? If you have an Apple Pencil go into settings and toggle off Scribble. You should be able to get the stationary keyboard back. Otherwise please share a screenshot of what you are seeing.